From 58d9211d2535f961191c74270524f9e600bfdf38 Mon Sep 17 00:00:00 2001 From: Enzo Volkmann Date: Sun, 7 Jan 2018 23:05:55 +0100 Subject: [PATCH 1/7] Added longestString() --- snippets/longestString.md | 15 +++++++++++++++ 1 file changed, 15 insertions(+) create mode 100644 snippets/longestString.md diff --git a/snippets/longestString.md b/snippets/longestString.md new file mode 100644 index 000000000..c8d02ca4d --- /dev/null +++ b/snippets/longestString.md @@ -0,0 +1,15 @@ +### longestString + +Takes an array of strings and returns the longestString one. + +Uses the [rest operator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters) +to handle arrays as well as an indefinite amount of single arguments. + +```js +const longestString = (...strings) => [...strings].reduce((a, b) => a.length > b.length ? a : b); +``` + +```js +longestString('this', 'is', 'a', 'testcase') // 'testcase' +longestString(['a', 'ab', 'abc']) // 'abc' +``` From a44f2b8f57a66dbe245ea0142692dae5ce59acf4 Mon Sep 17 00:00:00 2001 From: Enzo Volkmann Date: Sun, 7 Jan 2018 23:08:48 +0100 Subject: [PATCH 2/7] Update longestString() --- snippets/longestString.md | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/snippets/longestString.md b/snippets/longestString.md index c8d02ca4d..03539dbe2 100644 --- a/snippets/longestString.md +++ b/snippets/longestString.md @@ -1,9 +1,10 @@ ### longestString -Takes an array of strings and returns the longestString one. +Takes an array of strings and returns the longest one. Uses the [rest operator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters) to handle arrays as well as an indefinite amount of single arguments. +Strings are compared using `Array.reduce()`. ```js const longestString = (...strings) => [...strings].reduce((a, b) => a.length > b.length ? a : b); From 02bdb13193569b1eda4c0f239d6ada06e0f5f122 Mon Sep 17 00:00:00 2001 From: Enzo Volkmann Date: Sun, 7 Jan 2018 23:09:54 +0100 Subject: [PATCH 3/7] Updated README.md using `npm run builder` --- README.md | 6066 ++++++++++++++++++++++++++--------------------------- 1 file changed, 3033 insertions(+), 3033 deletions(-) diff --git a/README.md b/README.md index 79ba0b7b9..1cafb8550 100644 --- a/README.md +++ b/README.md @@ -1,72 +1,72 @@ -![Logo](/logo.png) - -# 30 seconds of code - -[![License](https://img.shields.io/badge/license-CC0--1.0-blue.svg)](https://github.com/Chalarangelo/30-seconds-of-code/blob/master/LICENSE) [![npm Downloads](https://img.shields.io/npm/dt/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![npm Version](https://img.shields.io/npm/v/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![Gitter chat](https://img.shields.io/badge/chat-on%20gitter-4FB999.svg)](https://gitter.im/30-seconds-of-code/Lobby) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](http://makeapullrequest.com) [![Travis Build](https://travis-ci.org/Chalarangelo/30-seconds-of-code.svg?branch=master)](https://travis-ci.org/Chalarangelo/30-seconds-of-code) [![Insight.io](https://img.shields.io/badge/insight.io-Ready-brightgreen.svg)](https://insight.io/github.com/Chalarangelo/30-seconds-of-code/tree/master/?source=0) [![js-semistandard-style](https://img.shields.io/badge/code%20style-semistandard-brightgreen.svg)](https://github.com/Flet/semistandard) [![ProductHunt](https://img.shields.io/badge/producthunt-vote-orange.svg)](https://www.producthunt.com/posts/30-seconds-of-code) - - -> Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less. - - -- Use Ctrl + F or command + F to search for a snippet. -- Contributions welcome, please read the [contribution guide](CONTRIBUTING.md). -- Snippets are written in ES6, use the [Babel transpiler](https://babeljs.io/) to ensure backwards-compatibility. -- You can import these snippets into your text editor of choice (VSCode, Atom, Sublime) using the files found in [this repo](https://github.com/Rob-Rychs/30-seconds-of-code-texteditorsnippets). -- You can import these snippets into Alfred 3, using [this file](https://github.com/lslvxy/30-seconds-of-code-alfredsnippets). - -#### Package - -⚠️ **WARNING:** Snippets are not production ready. - -You can find a package with all the snippets on [npm](https://www.npmjs.com/package/30-seconds-of-code). - -``` -npm install 30-seconds-of-code -``` - -CDN links -- [ES2017 Full (UMD)](https://unpkg.com/30-seconds-of-code) -- [ES5 Minified (UMD)](https://unpkg.com/30-seconds-of-code/dist/_30s.es5.min.js) - -
- -**Browser** - -> IMPORTANT: replace the `src` with the full version link and desired target spec (such as ES5 minified)): - -```html - - -``` - -**Node** - -```js -// CommonJS -const _30s = require('30-seconds-of-code'); -_30s.average(1, 2, 3); - -// ES Modules -import _30s from '30-seconds-of-code'; -_30s.average(1, 2, 3); -``` - -To import snippets directly: - -```js -// CommonJS -const { average } = require('30-seconds-of-code'); -average(1, 2, 3); - -// ES Modules -import { average } from '30-seconds-of-code'; -average(1, 2, 3); -``` -
- -## Table of Contents +![Logo](/logo.png) + +# 30 seconds of code + +[![License](https://img.shields.io/badge/license-CC0--1.0-blue.svg)](https://github.com/Chalarangelo/30-seconds-of-code/blob/master/LICENSE) [![npm Downloads](https://img.shields.io/npm/dt/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![npm Version](https://img.shields.io/npm/v/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![Gitter chat](https://img.shields.io/badge/chat-on%20gitter-4FB999.svg)](https://gitter.im/30-seconds-of-code/Lobby) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](http://makeapullrequest.com) [![Travis Build](https://travis-ci.org/Chalarangelo/30-seconds-of-code.svg?branch=master)](https://travis-ci.org/Chalarangelo/30-seconds-of-code) [![Insight.io](https://img.shields.io/badge/insight.io-Ready-brightgreen.svg)](https://insight.io/github.com/Chalarangelo/30-seconds-of-code/tree/master/?source=0) [![js-semistandard-style](https://img.shields.io/badge/code%20style-semistandard-brightgreen.svg)](https://github.com/Flet/semistandard) [![ProductHunt](https://img.shields.io/badge/producthunt-vote-orange.svg)](https://www.producthunt.com/posts/30-seconds-of-code) + + +> Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less. + + +- Use Ctrl + F or command + F to search for a snippet. +- Contributions welcome, please read the [contribution guide](CONTRIBUTING.md). +- Snippets are written in ES6, use the [Babel transpiler](https://babeljs.io/) to ensure backwards-compatibility. +- You can import these snippets into your text editor of choice (VSCode, Atom, Sublime) using the files found in [this repo](https://github.com/Rob-Rychs/30-seconds-of-code-texteditorsnippets). +- You can import these snippets into Alfred 3, using [this file](https://github.com/lslvxy/30-seconds-of-code-alfredsnippets). + +#### Package + +⚠️ **WARNING:** Snippets are not production ready. + +You can find a package with all the snippets on [npm](https://www.npmjs.com/package/30-seconds-of-code). + +``` +npm install 30-seconds-of-code +``` + +CDN links +- [ES2017 Full (UMD)](https://unpkg.com/30-seconds-of-code) +- [ES5 Minified (UMD)](https://unpkg.com/30-seconds-of-code/dist/_30s.es5.min.js) + +
+ +**Browser** + +> IMPORTANT: replace the `src` with the full version link and desired target spec (such as ES5 minified)): + +```html + + +``` + +**Node** + +```js +// CommonJS +const _30s = require('30-seconds-of-code'); +_30s.average(1, 2, 3); + +// ES Modules +import _30s from '30-seconds-of-code'; +_30s.average(1, 2, 3); +``` + +To import snippets directly: + +```js +// CommonJS +const { average } = require('30-seconds-of-code'); +average(1, 2, 3); + +// ES Modules +import { average } from '30-seconds-of-code'; +average(1, 2, 3); +``` +
+ +## Table of Contents ### 🔌 Adapter @@ -430,55 +430,55 @@ Object.assign(b, a); // == b
[⬆ Back to top](#table-of-contents) -### pipeFunctions - -Performs left-to-right function composition. - -Use `Array.reduce()` with the spread operator (`...`) to perform left-to-right function composition. -The first (leftmost) function can accept one or more arguments; the remaining functions must be unary. - -```js -const pipeFunctions = (...fns) => fns.reduce((f, g) => (...args) => g(f(...args))); -``` - +### pipeFunctions + +Performs left-to-right function composition. + +Use `Array.reduce()` with the spread operator (`...`) to perform left-to-right function composition. +The first (leftmost) function can accept one or more arguments; the remaining functions must be unary. + +```js +const pipeFunctions = (...fns) => fns.reduce((f, g) => (...args) => g(f(...args))); +``` +
Examples -```js -const add5 = x => x + 5; -const multiply = (x, y) => x * y; -const multiplyAndAdd5 = pipeFunctions(multiply, add5); -multiplyAndAdd5(5, 2); // 15 -``` +```js +const add5 = x => x + 5; +const multiply = (x, y) => x * y; +const multiplyAndAdd5 = pipeFunctions(multiply, add5); +multiplyAndAdd5(5, 2); // 15 +```

[⬆ Back to top](#table-of-contents) -### promisify - -Converts an asynchronous function to return a promise. - -Use currying to return a function returning a `Promise` that calls the original function. -Use the `...rest` operator to pass in all the parameters. - -*In Node 8+, you can use [`util.promisify`](https://nodejs.org/api/util.html#util_util_promisify_original)* - -```js -const promisify = func => (...args) => - new Promise((resolve, reject) => - func(...args, (err, result) => (err ? reject(err) : resolve(result))) - ); -``` - +### promisify + +Converts an asynchronous function to return a promise. + +Use currying to return a function returning a `Promise` that calls the original function. +Use the `...rest` operator to pass in all the parameters. + +*In Node 8+, you can use [`util.promisify`](https://nodejs.org/api/util.html#util_util_promisify_original)* + +```js +const promisify = func => (...args) => + new Promise((resolve, reject) => + func(...args, (err, result) => (err ? reject(err) : resolve(result))) + ); +``` +
Examples -```js -const delay = promisify((d, cb) => setTimeout(cb, d)); -delay(2000).then(() => console.log('Hi!')); // // Promise resolves after 2s -``` +```js +const delay = promisify((d, cb) => setTimeout(cb, d)); +delay(2000).then(() => console.log('Hi!')); // // Promise resolves after 2s +```
@@ -510,1214 +510,1214 @@ arrayMax([1, 2, 3]); // 3 --- ## 📚 Array -### chunk - -Chunks an array into smaller arrays of a specified size. - -Use `Array.from()` to create a new array, that fits the number of chunks that will be produced. -Use `Array.slice()` to map each element of the new array to a chunk the length of `size`. -If the original array can't be split evenly, the final chunk will contain the remaining elements. - -```js -const chunk = (arr, size) => - Array.from({ length: Math.ceil(arr.length / size) }, (v, i) => - arr.slice(i * size, i * size + size) - ); -``` - +### chunk + +Chunks an array into smaller arrays of a specified size. + +Use `Array.from()` to create a new array, that fits the number of chunks that will be produced. +Use `Array.slice()` to map each element of the new array to a chunk the length of `size`. +If the original array can't be split evenly, the final chunk will contain the remaining elements. + +```js +const chunk = (arr, size) => + Array.from({ length: Math.ceil(arr.length / size) }, (v, i) => + arr.slice(i * size, i * size + size) + ); +``` +
Examples -```js -chunk([1, 2, 3, 4, 5], 2); // [[1,2],[3,4],[5]] -``` +```js +chunk([1, 2, 3, 4, 5], 2); // [[1,2],[3,4],[5]] +```

[⬆ Back to top](#table-of-contents) -### compact - -Removes falsey values from an array. - -Use `Array.filter()` to filter out falsey values (`false`, `null`, `0`, `""`, `undefined`, and `NaN`). - -```js -const compact = arr => arr.filter(Boolean); -``` - +### compact + +Removes falsey values from an array. + +Use `Array.filter()` to filter out falsey values (`false`, `null`, `0`, `""`, `undefined`, and `NaN`). + +```js +const compact = arr => arr.filter(Boolean); +``` +
Examples -```js -compact([0, 1, false, 2, '', 3, 'a', 'e' * 23, NaN, 's', 34]); // [ 1, 2, 3, 'a', 's', 34 ] -``` +```js +compact([0, 1, false, 2, '', 3, 'a', 'e' * 23, NaN, 's', 34]); // [ 1, 2, 3, 'a', 's', 34 ] +```

[⬆ Back to top](#table-of-contents) -### countOccurrences - -Counts the occurrences of a value in an array. - -Use `Array.reduce()` to increment a counter each time you encounter the specific value inside the array. - -```js -const countOccurrences = (arr, val) => arr.reduce((a, v) => (v === val ? a + 1 : a + 0), 0); -``` - +### countOccurrences + +Counts the occurrences of a value in an array. + +Use `Array.reduce()` to increment a counter each time you encounter the specific value inside the array. + +```js +const countOccurrences = (arr, val) => arr.reduce((a, v) => (v === val ? a + 1 : a + 0), 0); +``` +
Examples -```js -countOccurrences([1, 1, 2, 1, 2, 3], 1); // 3 -``` +```js +countOccurrences([1, 1, 2, 1, 2, 3], 1); // 3 +```

[⬆ Back to top](#table-of-contents) -### deepFlatten - -Deep flattens an array. - -Use recursion. -Use `Array.concat()` with an empty array (`[]`) and the spread operator (`...`) to flatten an array. -Recursively flatten each element that is an array. - -```js -const deepFlatten = arr => [].concat(...arr.map(v => (Array.isArray(v) ? deepFlatten(v) : v))); -``` - +### deepFlatten + +Deep flattens an array. + +Use recursion. +Use `Array.concat()` with an empty array (`[]`) and the spread operator (`...`) to flatten an array. +Recursively flatten each element that is an array. + +```js +const deepFlatten = arr => [].concat(...arr.map(v => (Array.isArray(v) ? deepFlatten(v) : v))); +``` +
Examples -```js -deepFlatten([1, [2], [[3], 4], 5]); // [1,2,3,4,5] -``` +```js +deepFlatten([1, [2], [[3], 4], 5]); // [1,2,3,4,5] +```

[⬆ Back to top](#table-of-contents) -### difference - -Returns the difference between two arrays. - -Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values not contained in `b`. - -```js -const difference = (a, b) => { - const s = new Set(b); - return a.filter(x => !s.has(x)); -}; -``` - +### difference + +Returns the difference between two arrays. + +Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values not contained in `b`. + +```js +const difference = (a, b) => { + const s = new Set(b); + return a.filter(x => !s.has(x)); +}; +``` +
Examples -```js -difference([1, 2, 3], [1, 2, 4]); // [3] -``` +```js +difference([1, 2, 3], [1, 2, 4]); // [3] +```

[⬆ Back to top](#table-of-contents) -### differenceWith - -Filters out all values from an array for which the comparator function does not return `true`. - -Use `Array.filter()` and `Array.findIndex()` to find the appropriate values. - -```js -const differenceWith = (arr, val, comp) => arr.filter(a => val.findIndex(b => comp(a, b)) === -1); -``` - +### differenceWith + +Filters out all values from an array for which the comparator function does not return `true`. + +Use `Array.filter()` and `Array.findIndex()` to find the appropriate values. + +```js +const differenceWith = (arr, val, comp) => arr.filter(a => val.findIndex(b => comp(a, b)) === -1); +``` +
Examples -```js -differenceWith([1, 1.2, 1.5, 3, 0], [1.9, 3, 0], (a, b) => Math.round(a) === Math.round(b)); // [1, 1.2] -``` +```js +differenceWith([1, 1.2, 1.5, 3, 0], [1.9, 3, 0], (a, b) => Math.round(a) === Math.round(b)); // [1, 1.2] +```

[⬆ Back to top](#table-of-contents) -### distinctValuesOfArray - -Returns all the distinct values of an array. - -Use ES6 `Set` and the `...rest` operator to discard all duplicated values. - -```js -const distinctValuesOfArray = arr => [...new Set(arr)]; -``` - +### distinctValuesOfArray + +Returns all the distinct values of an array. + +Use ES6 `Set` and the `...rest` operator to discard all duplicated values. + +```js +const distinctValuesOfArray = arr => [...new Set(arr)]; +``` +
Examples -```js -distinctValuesOfArray([1, 2, 2, 3, 4, 4, 5]); // [1,2,3,4,5] -``` +```js +distinctValuesOfArray([1, 2, 2, 3, 4, 4, 5]); // [1,2,3,4,5] +```

[⬆ Back to top](#table-of-contents) -### dropElements - -Removes elements in an array until the passed function returns `true`. Returns the remaining elements in the array. - -Loop through the array, using `Array.slice()` to drop the first element of the array until the returned value from the function is `true`. -Returns the remaining elements. - -```js -const dropElements = (arr, func) => { - while (arr.length > 0 && !func(arr[0])) arr = arr.slice(1); - return arr; -}; -``` - +### dropElements + +Removes elements in an array until the passed function returns `true`. Returns the remaining elements in the array. + +Loop through the array, using `Array.slice()` to drop the first element of the array until the returned value from the function is `true`. +Returns the remaining elements. + +```js +const dropElements = (arr, func) => { + while (arr.length > 0 && !func(arr[0])) arr = arr.slice(1); + return arr; +}; +``` +
Examples -```js -dropElements([1, 2, 3, 4], n => n >= 3); // [3,4] -``` +```js +dropElements([1, 2, 3, 4], n => n >= 3); // [3,4] +```

[⬆ Back to top](#table-of-contents) -### dropRight - -Returns a new array with `n` elements removed from the right. - -Use `Array.slice()` to slice the remove the specified number of elements from the right. - -```js -const dropRight = (arr, n = 1) => arr.slice(0, -n); -``` - +### dropRight + +Returns a new array with `n` elements removed from the right. + +Use `Array.slice()` to slice the remove the specified number of elements from the right. + +```js +const dropRight = (arr, n = 1) => arr.slice(0, -n); +``` +
Examples -```js -dropRight([1, 2, 3]); // [1,2] -dropRight([1, 2, 3], 2); // [1] -dropRight([1, 2, 3], 42); // [] -``` +```js +dropRight([1, 2, 3]); // [1,2] +dropRight([1, 2, 3], 2); // [1] +dropRight([1, 2, 3], 42); // [] +```

[⬆ Back to top](#table-of-contents) -### everyNth - -Returns every nth element in an array. - -Use `Array.filter()` to create a new array that contains every nth element of a given array. - -```js -const everyNth = (arr, nth) => arr.filter((e, i) => i % nth === nth - 1); -``` - +### everyNth + +Returns every nth element in an array. + +Use `Array.filter()` to create a new array that contains every nth element of a given array. + +```js +const everyNth = (arr, nth) => arr.filter((e, i) => i % nth === nth - 1); +``` +
Examples -```js -everyNth([1, 2, 3, 4, 5, 6], 2); // [ 2, 4, 6 ] -``` +```js +everyNth([1, 2, 3, 4, 5, 6], 2); // [ 2, 4, 6 ] +```

[⬆ Back to top](#table-of-contents) -### filterNonUnique - -Filters out the non-unique values in an array. - -Use `Array.filter()` for an array containing only the unique values. - -```js -const filterNonUnique = arr => arr.filter(i => arr.indexOf(i) === arr.lastIndexOf(i)); -``` - +### filterNonUnique + +Filters out the non-unique values in an array. + +Use `Array.filter()` for an array containing only the unique values. + +```js +const filterNonUnique = arr => arr.filter(i => arr.indexOf(i) === arr.lastIndexOf(i)); +``` +
Examples -```js -filterNonUnique([1, 2, 2, 3, 4, 4, 5]); // [1,3,5] -``` +```js +filterNonUnique([1, 2, 2, 3, 4, 4, 5]); // [1,3,5] +```

[⬆ Back to top](#table-of-contents) -### flatten - -Flattens an array. - -Use a new array, `Array.concat()` and the spread operator (`...`) to cause a shallow denesting of any contained arrays. - -```js -const flatten = arr => [].concat(...arr); -``` - +### flatten + +Flattens an array. + +Use a new array, `Array.concat()` and the spread operator (`...`) to cause a shallow denesting of any contained arrays. + +```js +const flatten = arr => [].concat(...arr); +``` +
Examples -```js -flatten([1, [2], 3, 4]); // [1,2,3,4] -``` +```js +flatten([1, [2], 3, 4]); // [1,2,3,4] +```

[⬆ Back to top](#table-of-contents) -### flattenDepth - -Flattens an array up to the specified depth. - -Use recursion, decrementing `depth` by 1 for each level of depth. -Use `Array.reduce()` and `Array.concat()` to merge elements or arrays. -Base case, for `depth` equal to `1` stops recursion. -Omit the second element, `depth` to flatten only to a depth of `1` (single flatten). - -```js -const flattenDepth = (arr, depth = 1) => - depth != 1 - ? arr.reduce((a, v) => a.concat(Array.isArray(v) ? flattenDepth(v, depth - 1) : v), []) - : arr.reduce((a, v) => a.concat(v), []); -``` - +### flattenDepth + +Flattens an array up to the specified depth. + +Use recursion, decrementing `depth` by 1 for each level of depth. +Use `Array.reduce()` and `Array.concat()` to merge elements or arrays. +Base case, for `depth` equal to `1` stops recursion. +Omit the second element, `depth` to flatten only to a depth of `1` (single flatten). + +```js +const flattenDepth = (arr, depth = 1) => + depth != 1 + ? arr.reduce((a, v) => a.concat(Array.isArray(v) ? flattenDepth(v, depth - 1) : v), []) + : arr.reduce((a, v) => a.concat(v), []); +``` +
Examples -```js -flattenDepth([1, [2], 3, 4]); // [1,2,3,4] -``` +```js +flattenDepth([1, [2], 3, 4]); // [1,2,3,4] +```

[⬆ Back to top](#table-of-contents) -### groupBy - -Groups the elements of an array based on the given function. - -Use `Array.map()` to map the values of an array to a function or property name. -Use `Array.reduce()` to create an object, where the keys are produced from the mapped results. - -```js -const groupBy = (arr, func) => - arr.map(typeof func === 'function' ? func : val => val[func]).reduce((acc, val, i) => { - acc[val] = (acc[val] || []).concat(arr[i]); - return acc; - }, {}); -``` - +### groupBy + +Groups the elements of an array based on the given function. + +Use `Array.map()` to map the values of an array to a function or property name. +Use `Array.reduce()` to create an object, where the keys are produced from the mapped results. + +```js +const groupBy = (arr, func) => + arr.map(typeof func === 'function' ? func : val => val[func]).reduce((acc, val, i) => { + acc[val] = (acc[val] || []).concat(arr[i]); + return acc; + }, {}); +``` +
Examples -```js -groupBy([6.1, 4.2, 6.3], Math.floor); // {4: [4.2], 6: [6.1, 6.3]} -groupBy(['one', 'two', 'three'], 'length'); // {3: ['one', 'two'], 5: ['three']} -``` +```js +groupBy([6.1, 4.2, 6.3], Math.floor); // {4: [4.2], 6: [6.1, 6.3]} +groupBy(['one', 'two', 'three'], 'length'); // {3: ['one', 'two'], 5: ['three']} +```

[⬆ Back to top](#table-of-contents) -### head - -Returns the head of a list. - -Use `arr[0]` to return the first element of the passed array. - -```js -const head = arr => arr[0]; -``` - +### head + +Returns the head of a list. + +Use `arr[0]` to return the first element of the passed array. + +```js +const head = arr => arr[0]; +``` +
Examples -```js -head([1, 2, 3]); // 1 -``` +```js +head([1, 2, 3]); // 1 +```

[⬆ Back to top](#table-of-contents) -### indexOfAll - -Returns all indices of `val` in an array. If `val` never occurs, returns `[-1]`. - -Use `Array.forEach()` to loop over elements and `Array.push()` to store indices for matching elements. -Return `[-1]` if `length` of the array of indices is `0`, otherwise return the array of indices. - -```js -const indexOfAll = (arr, val) => { - const indices = []; - arr.forEach((el, i) => el === val && indices.push(i)); - return indices.length ? indices : [-1]; -}; -``` - +### indexOfAll + +Returns all indices of `val` in an array. If `val` never occurs, returns `[-1]`. + +Use `Array.forEach()` to loop over elements and `Array.push()` to store indices for matching elements. +Return `[-1]` if `length` of the array of indices is `0`, otherwise return the array of indices. + +```js +const indexOfAll = (arr, val) => { + const indices = []; + arr.forEach((el, i) => el === val && indices.push(i)); + return indices.length ? indices : [-1]; +}; +``` +
Examples -```js -indexOfAll([1, 2, 3, 1, 2, 3], 1); // [0,3] -indexOfAll([1, 2, 3], 4); // [-1] -``` +```js +indexOfAll([1, 2, 3, 1, 2, 3], 1); // [0,3] +indexOfAll([1, 2, 3], 4); // [-1] +```

[⬆ Back to top](#table-of-contents) -### initial - -Returns all the elements of an array except the last one. - -Use `arr.slice(0,-1)` to return all but the last element of the array. - -```js -const initial = arr => arr.slice(0, -1); -``` - +### initial + +Returns all the elements of an array except the last one. + +Use `arr.slice(0,-1)` to return all but the last element of the array. + +```js +const initial = arr => arr.slice(0, -1); +``` +
Examples -```js -initial([1, 2, 3]); // [1,2] -``` +```js +initial([1, 2, 3]); // [1,2] +```

[⬆ Back to top](#table-of-contents) -### initialize2DArray - -Initializes a 2D array of given width and height and value. - -Use `Array.map()` to generate h rows where each is a new array of size w initialize with value. If the value is not provided, default to `null`. - -```js -const initialize2DArray = (w, h, val = null) => - Array(h) - .fill() - .map(() => Array(w).fill(val)); -``` - +### initialize2DArray + +Initializes a 2D array of given width and height and value. + +Use `Array.map()` to generate h rows where each is a new array of size w initialize with value. If the value is not provided, default to `null`. + +```js +const initialize2DArray = (w, h, val = null) => + Array(h) + .fill() + .map(() => Array(w).fill(val)); +``` +
Examples -```js -initialize2DArray(2, 2, 0); // [[0,0], [0,0]] -``` +```js +initialize2DArray(2, 2, 0); // [[0,0], [0,0]] +```

[⬆ Back to top](#table-of-contents) -### initializeArrayWithRange - -Initializes an array containing the numbers in the specified range where `start` and `end` are inclusive with there common difference `step`. - -Use `Array.from(Math.ceil((end+1-start)/step))` to create an array of the desired length(the amounts of elements is equal to `(end-start)/step` or `(end+1-start)/step` for inclusive end), `Array.map()` to fill with the desired values in a range. -You can omit `start` to use a default value of `0`. -You can omit `step` to use a default value of `1`. - -```js -const initializeArrayWithRange = (end, start = 0, step = 1) => - Array.from({ length: Math.ceil((end + 1 - start) / step) }).map((v, i) => i * step + start); -``` - +### initializeArrayWithRange + +Initializes an array containing the numbers in the specified range where `start` and `end` are inclusive with there common difference `step`. + +Use `Array.from(Math.ceil((end+1-start)/step))` to create an array of the desired length(the amounts of elements is equal to `(end-start)/step` or `(end+1-start)/step` for inclusive end), `Array.map()` to fill with the desired values in a range. +You can omit `start` to use a default value of `0`. +You can omit `step` to use a default value of `1`. + +```js +const initializeArrayWithRange = (end, start = 0, step = 1) => + Array.from({ length: Math.ceil((end + 1 - start) / step) }).map((v, i) => i * step + start); +``` +
Examples -```js -initializeArrayWithRange(5); // [0,1,2,3,4,5] -initializeArrayWithRange(7, 3); // [3,4,5,6,7] -initializeArrayWithRange(9, 0, 2); // [0,2,4,6,8] -``` +```js +initializeArrayWithRange(5); // [0,1,2,3,4,5] +initializeArrayWithRange(7, 3); // [3,4,5,6,7] +initializeArrayWithRange(9, 0, 2); // [0,2,4,6,8] +```

[⬆ Back to top](#table-of-contents) -### initializeArrayWithValues - -Initializes and fills an array with the specified values. - -Use `Array(n)` to create an array of the desired length, `fill(v)` to fill it with the desired values. -You can omit `val` to use a default value of `0`. - -```js -const initializeArrayWithValues = (n, val = 0) => Array(n).fill(val); -``` - +### initializeArrayWithValues + +Initializes and fills an array with the specified values. + +Use `Array(n)` to create an array of the desired length, `fill(v)` to fill it with the desired values. +You can omit `val` to use a default value of `0`. + +```js +const initializeArrayWithValues = (n, val = 0) => Array(n).fill(val); +``` +
Examples -```js -initializeArrayWithValues(5, 2); // [2,2,2,2,2] -``` +```js +initializeArrayWithValues(5, 2); // [2,2,2,2,2] +```

[⬆ Back to top](#table-of-contents) -### intersection - -Returns a list of elements that exist in both arrays. - -Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values contained in `b`. - -```js -const intersection = (a, b) => { - const s = new Set(b); - return a.filter(x => s.has(x)); -}; -``` - +### intersection + +Returns a list of elements that exist in both arrays. + +Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values contained in `b`. + +```js +const intersection = (a, b) => { + const s = new Set(b); + return a.filter(x => s.has(x)); +}; +``` +
Examples -```js -intersection([1, 2, 3], [4, 3, 2]); // [2,3] -``` +```js +intersection([1, 2, 3], [4, 3, 2]); // [2,3] +```

[⬆ Back to top](#table-of-contents) -### isSorted - -Returns `1` if the array is sorted in ascending order, `-1` if it is sorted in descending order or `0` if it is not sorted. - -Calculate the ordering `direction` for the first two elements. -Use `Object.entries()` to loop over array objects and compare them in pairs. -Return `0` if the `direction` changes or the `direction` if the last element is reached. - -```js -const isSorted = arr => { - const direction = arr[0] > arr[1] ? -1 : 1; - for (let [i, val] of arr.entries()) - if (i === arr.length - 1) return direction; - else if ((val - arr[i + 1]) * direction > 0) return 0; -}; -``` - +### isSorted + +Returns `1` if the array is sorted in ascending order, `-1` if it is sorted in descending order or `0` if it is not sorted. + +Calculate the ordering `direction` for the first two elements. +Use `Object.entries()` to loop over array objects and compare them in pairs. +Return `0` if the `direction` changes or the `direction` if the last element is reached. + +```js +const isSorted = arr => { + const direction = arr[0] > arr[1] ? -1 : 1; + for (let [i, val] of arr.entries()) + if (i === arr.length - 1) return direction; + else if ((val - arr[i + 1]) * direction > 0) return 0; +}; +``` +
Examples -```js -isSorted([0, 1, 2, 2]); // 1 -isSorted([4, 3, 2]); // -1 -isSorted([4, 3, 5]); // 0 -``` +```js +isSorted([0, 1, 2, 2]); // 1 +isSorted([4, 3, 2]); // -1 +isSorted([4, 3, 5]); // 0 +```

[⬆ Back to top](#table-of-contents) -### join - -Joins all elements of an array into a string and returns this string. Uses a separator and an end separator. - -Use `Array.reduce()` to combine elements into a string. -Omit the second argument, `separator`, to use a default separator of `','`. -Omit the third argument, `end`, to use the same value as `separator` by default. - -```js -const join = (arr, separator = ',', end = separator) => - arr.reduce( - (acc, val, i) => - i == arr.length - 2 - ? acc + val + end - : i == arr.length - 1 ? acc + val : acc + val + separator, - '' - ); -``` - +### join + +Joins all elements of an array into a string and returns this string. Uses a separator and an end separator. + +Use `Array.reduce()` to combine elements into a string. +Omit the second argument, `separator`, to use a default separator of `','`. +Omit the third argument, `end`, to use the same value as `separator` by default. + +```js +const join = (arr, separator = ',', end = separator) => + arr.reduce( + (acc, val, i) => + i == arr.length - 2 + ? acc + val + end + : i == arr.length - 1 ? acc + val : acc + val + separator, + '' + ); +``` +
Examples -```js -join(['pen', 'pineapple', 'apple', 'pen'], ',', '&'); // "pen,pineapple,apple&pen" -join(['pen', 'pineapple', 'apple', 'pen'], ','); // "pen,pineapple,apple,pen" -join(['pen', 'pineapple', 'apple', 'pen']); // "pen,pineapple,apple,pen" -``` +```js +join(['pen', 'pineapple', 'apple', 'pen'], ',', '&'); // "pen,pineapple,apple&pen" +join(['pen', 'pineapple', 'apple', 'pen'], ','); // "pen,pineapple,apple,pen" +join(['pen', 'pineapple', 'apple', 'pen']); // "pen,pineapple,apple,pen" +```

[⬆ Back to top](#table-of-contents) -### last - -Returns the last element in an array. - -Use `arr.length - 1` to compute the index of the last element of the given array and returning it. - -```js -const last = arr => arr[arr.length - 1]; -``` - +### last + +Returns the last element in an array. + +Use `arr.length - 1` to compute the index of the last element of the given array and returning it. + +```js +const last = arr => arr[arr.length - 1]; +``` +
Examples -```js -last([1, 2, 3]); // 3 -``` +```js +last([1, 2, 3]); // 3 +```

[⬆ Back to top](#table-of-contents) -### mapObject - -Maps the values of an array to an object using a function, where the key-value pairs consist of the original value as the key and the mapped value. - -Use an anonymous inner function scope to declare an undefined memory space, using closures to store a return value. Use a new `Array` to store the array with a map of the function over its data set and a comma operator to return a second step, without needing to move from one context to another (due to closures and order of operations). - -```js -const mapObject = (arr, fn) => - (a => ( - (a = [arr, arr.map(fn)]), a[0].reduce((acc, val, ind) => ((acc[val] = a[1][ind]), acc), {}) - ))(); -``` - +### mapObject + +Maps the values of an array to an object using a function, where the key-value pairs consist of the original value as the key and the mapped value. + +Use an anonymous inner function scope to declare an undefined memory space, using closures to store a return value. Use a new `Array` to store the array with a map of the function over its data set and a comma operator to return a second step, without needing to move from one context to another (due to closures and order of operations). + +```js +const mapObject = (arr, fn) => + (a => ( + (a = [arr, arr.map(fn)]), a[0].reduce((acc, val, ind) => ((acc[val] = a[1][ind]), acc), {}) + ))(); +``` +
Examples -```js -const squareIt = arr => mapObject(arr, a => a * a); -squareIt([1, 2, 3]); // { 1: 1, 2: 4, 3: 9 } -``` +```js +const squareIt = arr => mapObject(arr, a => a * a); +squareIt([1, 2, 3]); // { 1: 1, 2: 4, 3: 9 } +```

[⬆ Back to top](#table-of-contents) -### maxN - -Returns the `n` maximum elements from the provided array. If `n` is greater than or equal to the provided array's length, then return the original array(sorted in descending order). - -Use `Array.sort()` combined with the spread operator (`...`) to create a shallow clone of the array and sort it in descending order. -Use `Array.slice()` to get the specified number of elements. -Omit the second argument, `n`, to get a one-element array. - -```js -const maxN = (arr, n = 1) => [...arr].sort((a, b) => b - a).slice(0, n); -``` - +### maxN + +Returns the `n` maximum elements from the provided array. If `n` is greater than or equal to the provided array's length, then return the original array(sorted in descending order). + +Use `Array.sort()` combined with the spread operator (`...`) to create a shallow clone of the array and sort it in descending order. +Use `Array.slice()` to get the specified number of elements. +Omit the second argument, `n`, to get a one-element array. + +```js +const maxN = (arr, n = 1) => [...arr].sort((a, b) => b - a).slice(0, n); +``` +
Examples -```js -maxN([1, 2, 3]); // [3] -maxN([1, 2, 3], 2); // [3,2] -``` +```js +maxN([1, 2, 3]); // [3] +maxN([1, 2, 3], 2); // [3,2] +```

[⬆ Back to top](#table-of-contents) -### minN - -Returns the `n` minimum elements from the provided array. If `n` is greater than or equal to the provided array's length, then return the original array(sorted in ascending order). - -Use `Array.sort()` combined with the spread operator (`...`) to create a shallow clone of the array and sort it in ascending order. -Use `Array.slice()` to get the specified number of elements. -Omit the second argument, `n`, to get a one-element array. - -```js -const minN = (arr, n = 1) => [...arr].sort((a, b) => a - b).slice(0, n); -``` +### minN + +Returns the `n` minimum elements from the provided array. If `n` is greater than or equal to the provided array's length, then return the original array(sorted in ascending order). + +Use `Array.sort()` combined with the spread operator (`...`) to create a shallow clone of the array and sort it in ascending order. +Use `Array.slice()` to get the specified number of elements. +Omit the second argument, `n`, to get a one-element array. + +```js +const minN = (arr, n = 1) => [...arr].sort((a, b) => a - b).slice(0, n); +```
Examples -```js -minN([1, 2, 3]); // [1] -minN([1, 2, 3], 2); // [1,2] -``` +```js +minN([1, 2, 3]); // [1] +minN([1, 2, 3], 2); // [1,2] +```

[⬆ Back to top](#table-of-contents) -### nthElement - -Returns the nth element of an array. - -Use `Array.slice()` to get an array containing the nth element at the first place. -If the index is out of bounds, return `[]`. -Omit the second argument, `n`, to get the first element of the array. - -```js -const nthElement = (arr, n = 0) => (n > 0 ? arr.slice(n, n + 1) : arr.slice(n))[0]; -``` - +### nthElement + +Returns the nth element of an array. + +Use `Array.slice()` to get an array containing the nth element at the first place. +If the index is out of bounds, return `[]`. +Omit the second argument, `n`, to get the first element of the array. + +```js +const nthElement = (arr, n = 0) => (n > 0 ? arr.slice(n, n + 1) : arr.slice(n))[0]; +``` +
Examples -```js -nthElement(['a', 'b', 'c'], 1); // 'b' -nthElement(['a', 'b', 'b'], -3); // 'a' -``` +```js +nthElement(['a', 'b', 'c'], 1); // 'b' +nthElement(['a', 'b', 'b'], -3); // 'a' +```

[⬆ Back to top](#table-of-contents) -### pick - -Picks the key-value pairs corresponding to the given keys from an object. - -Use `Array.reduce()` to convert the filtered/picked keys back to an object with the corresponding key-value pair if the key exists in the obj. - -```js -const pick = (obj, arr) => - arr.reduce((acc, curr) => (curr in obj && (acc[curr] = obj[curr]), acc), {}); -``` - +### pick + +Picks the key-value pairs corresponding to the given keys from an object. + +Use `Array.reduce()` to convert the filtered/picked keys back to an object with the corresponding key-value pair if the key exists in the obj. + +```js +const pick = (obj, arr) => + arr.reduce((acc, curr) => (curr in obj && (acc[curr] = obj[curr]), acc), {}); +``` +
Examples -```js -pick({ a: 1, b: '2', c: 3 }, ['a', 'c']); // { 'a': 1, 'c': 3 } -``` +```js +pick({ a: 1, b: '2', c: 3 }, ['a', 'c']); // { 'a': 1, 'c': 3 } +```

[⬆ Back to top](#table-of-contents) -### pull - -Mutates the original array to filter out the values specified. - -Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed. -Use `Array.length = 0` to mutate the passed in an array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values. - -_(For a snippet that does not mutate the original array see [`without`](#without))_ - -```js -const pull = (arr, ...args) => { - let argState = Array.isArray(args[0]) ? args[0] : args; - let pulled = arr.filter((v, i) => !argState.includes(v)); - arr.length = 0; - pulled.forEach(v => arr.push(v)); -}; -``` - +### pull + +Mutates the original array to filter out the values specified. + +Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed. +Use `Array.length = 0` to mutate the passed in an array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values. + +_(For a snippet that does not mutate the original array see [`without`](#without))_ + +```js +const pull = (arr, ...args) => { + let argState = Array.isArray(args[0]) ? args[0] : args; + let pulled = arr.filter((v, i) => !argState.includes(v)); + arr.length = 0; + pulled.forEach(v => arr.push(v)); +}; +``` +
Examples -```js -let myArray = ['a', 'b', 'c', 'a', 'b', 'c']; -pull(myArray, 'a', 'c'); // myArray = [ 'b', 'b' ] -``` +```js +let myArray = ['a', 'b', 'c', 'a', 'b', 'c']; +pull(myArray, 'a', 'c'); // myArray = [ 'b', 'b' ] +```

[⬆ Back to top](#table-of-contents) -### pullAtIndex - -Mutates the original array to filter out the values at the specified indexes. - -Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed. -Use `Array.length = 0` to mutate the passed in an array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values. -Use `Array.push()` to keep track of pulled values - -```js -const pullAtIndex = (arr, pullArr) => { - let removed = []; - let pulled = arr - .map((v, i) => (pullArr.includes(i) ? removed.push(v) : v)) - .filter((v, i) => !pullArr.includes(i)); - arr.length = 0; - pulled.forEach(v => arr.push(v)); - return removed; -}; -``` - +### pullAtIndex + +Mutates the original array to filter out the values at the specified indexes. + +Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed. +Use `Array.length = 0` to mutate the passed in an array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values. +Use `Array.push()` to keep track of pulled values + +```js +const pullAtIndex = (arr, pullArr) => { + let removed = []; + let pulled = arr + .map((v, i) => (pullArr.includes(i) ? removed.push(v) : v)) + .filter((v, i) => !pullArr.includes(i)); + arr.length = 0; + pulled.forEach(v => arr.push(v)); + return removed; +}; +``` +
Examples -```js -let myArray = ['a', 'b', 'c', 'd']; -let pulled = pullAtIndex(myArray, [1, 3]); // myArray = [ 'a', 'c' ] , pulled = [ 'b', 'd' ] -``` +```js +let myArray = ['a', 'b', 'c', 'd']; +let pulled = pullAtIndex(myArray, [1, 3]); // myArray = [ 'a', 'c' ] , pulled = [ 'b', 'd' ] +```

[⬆ Back to top](#table-of-contents) -### pullAtValue - -Mutates the original array to filter out the values specified. Returns the removed elements. - -Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed. -Use `Array.length = 0` to mutate the passed in an array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values. -Use `Array.push()` to keep track of pulled values - -```js -const pullAtValue = (arr, pullArr) => { - let removed = [], - pushToRemove = arr.forEach((v, i) => (pullArr.includes(v) ? removed.push(v) : v)), - mutateTo = arr.filter((v, i) => !pullArr.includes(v)); - arr.length = 0; - mutateTo.forEach(v => arr.push(v)); - return removed; -}; -``` - +### pullAtValue + +Mutates the original array to filter out the values specified. Returns the removed elements. + +Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed. +Use `Array.length = 0` to mutate the passed in an array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values. +Use `Array.push()` to keep track of pulled values + +```js +const pullAtValue = (arr, pullArr) => { + let removed = [], + pushToRemove = arr.forEach((v, i) => (pullArr.includes(v) ? removed.push(v) : v)), + mutateTo = arr.filter((v, i) => !pullArr.includes(v)); + arr.length = 0; + mutateTo.forEach(v => arr.push(v)); + return removed; +}; +``` +
Examples -```js -let myArray = ['a', 'b', 'c', 'd']; -let pulled = pullAtValue(myArray, ['b', 'd']); // myArray = [ 'a', 'c' ] , pulled = [ 'b', 'd' ] -``` +```js +let myArray = ['a', 'b', 'c', 'd']; +let pulled = pullAtValue(myArray, ['b', 'd']); // myArray = [ 'a', 'c' ] , pulled = [ 'b', 'd' ] +```

[⬆ Back to top](#table-of-contents) -### reducedFilter - -Filter an array of objects based on a condition while also filtering out unspecified keys. - -Use `Array.filter()` to filter the array based on the predicate `fn` so that it returns the objects for which the condition returned a truthy value. -On the filtered array, use `Array.map()` to return the new object using `Array.reduce()` to filter out the keys which were not supplied as the `keys` argument. - -```js -const reducedFilter = (data, keys, fn) => - data.filter(fn).map(el => - keys.reduce((acc, key) => { - acc[key] = el[key]; - return acc; - }, {}) - ); -``` - +### reducedFilter + +Filter an array of objects based on a condition while also filtering out unspecified keys. + +Use `Array.filter()` to filter the array based on the predicate `fn` so that it returns the objects for which the condition returned a truthy value. +On the filtered array, use `Array.map()` to return the new object using `Array.reduce()` to filter out the keys which were not supplied as the `keys` argument. + +```js +const reducedFilter = (data, keys, fn) => + data.filter(fn).map(el => + keys.reduce((acc, key) => { + acc[key] = el[key]; + return acc; + }, {}) + ); +``` +
Examples -```js -const data = [ - { - id: 1, - name: 'john', - age: 24 - }, - { - id: 2, - name: 'mike', - age: 50 - } -]; - -reducedFilter(data, ['id', 'name'], item => item.age > 24); // [{ id: 2, name: 'mike'}] -``` +```js +const data = [ + { + id: 1, + name: 'john', + age: 24 + }, + { + id: 2, + name: 'mike', + age: 50 + } +]; + +reducedFilter(data, ['id', 'name'], item => item.age > 24); // [{ id: 2, name: 'mike'}] +```

[⬆ Back to top](#table-of-contents) -### remove - -Removes elements from an array for which the given function returns `false`. - -Use `Array.filter()` to find array elements that return truthy values and `Array.reduce()` to remove elements using `Array.splice()`. -The `func` is invoked with three arguments (`value, index, array`). - -```js -const remove = (arr, func) => - Array.isArray(arr) - ? arr.filter(func).reduce((acc, val) => { - arr.splice(arr.indexOf(val), 1); - return acc.concat(val); - }, []) - : []; -``` - +### remove + +Removes elements from an array for which the given function returns `false`. + +Use `Array.filter()` to find array elements that return truthy values and `Array.reduce()` to remove elements using `Array.splice()`. +The `func` is invoked with three arguments (`value, index, array`). + +```js +const remove = (arr, func) => + Array.isArray(arr) + ? arr.filter(func).reduce((acc, val) => { + arr.splice(arr.indexOf(val), 1); + return acc.concat(val); + }, []) + : []; +``` +
Examples -```js -remove([1, 2, 3, 4], n => n % 2 == 0); // [2, 4] -``` +```js +remove([1, 2, 3, 4], n => n % 2 == 0); // [2, 4] +```

[⬆ Back to top](#table-of-contents) -### sample - -Returns a random element from an array. - -Use `Math.random()` to generate a random number, multiply it by `length` and round it of to the nearest whole number using `Math.floor()`. -This method also works with strings. - -```js -const sample = arr => arr[Math.floor(Math.random() * arr.length)]; -``` - +### sample + +Returns a random element from an array. + +Use `Math.random()` to generate a random number, multiply it by `length` and round it of to the nearest whole number using `Math.floor()`. +This method also works with strings. + +```js +const sample = arr => arr[Math.floor(Math.random() * arr.length)]; +``` +
Examples -```js -sample([3, 7, 9, 11]); // 9 -``` +```js +sample([3, 7, 9, 11]); // 9 +```

[⬆ Back to top](#table-of-contents) -### sampleSize - -Gets `n` random elements at unique keys from `array` up to the size of `array`. - -Shuffle the array using the [Fisher-Yates algorithm](https://github.com/chalarangelo/30-seconds-of-code#shuffle). -Use `Array.slice()` to get the first `n` elements. -Omit the second argument, `n` to get only one element at random from the array. - -```js -const sampleSize = ([...arr], n = 1) => { - let m = arr.length; - while (m) { - const i = Math.floor(Math.random() * m--); - [arr[m], arr[i]] = [arr[i], arr[m]]; - } - return arr.slice(0, n); -}; -``` - +### sampleSize + +Gets `n` random elements at unique keys from `array` up to the size of `array`. + +Shuffle the array using the [Fisher-Yates algorithm](https://github.com/chalarangelo/30-seconds-of-code#shuffle). +Use `Array.slice()` to get the first `n` elements. +Omit the second argument, `n` to get only one element at random from the array. + +```js +const sampleSize = ([...arr], n = 1) => { + let m = arr.length; + while (m) { + const i = Math.floor(Math.random() * m--); + [arr[m], arr[i]] = [arr[i], arr[m]]; + } + return arr.slice(0, n); +}; +``` +
Examples -```js -sampleSize([1, 2, 3], 2); // [3,1] -sampleSize([1, 2, 3], 4); // [2,3,1] -``` +```js +sampleSize([1, 2, 3], 2); // [3,1] +sampleSize([1, 2, 3], 4); // [2,3,1] +```

[⬆ Back to top](#table-of-contents) -### shuffle - -Randomizes the order of the values of an array, returning a new array. - -Uses the [Fisher-Yates algorithm](https://github.com/chalarangelo/30-seconds-of-code#shuffle) to reorder the elements of the array. - -```js -const shuffle = ([...arr]) => { - let m = arr.length; - while (m) { - const i = Math.floor(Math.random() * m--); - [arr[m], arr[i]] = [arr[i], arr[m]]; - } - return arr; -}; -``` - +### shuffle + +Randomizes the order of the values of an array, returning a new array. + +Uses the [Fisher-Yates algorithm](https://github.com/chalarangelo/30-seconds-of-code#shuffle) to reorder the elements of the array. + +```js +const shuffle = ([...arr]) => { + let m = arr.length; + while (m) { + const i = Math.floor(Math.random() * m--); + [arr[m], arr[i]] = [arr[i], arr[m]]; + } + return arr; +}; +``` +
Examples -```js -const foo = [1, 2, 3]; -shuffle(foo); // [2,3,1], foo = [1,2,3] -``` +```js +const foo = [1, 2, 3]; +shuffle(foo); // [2,3,1], foo = [1,2,3] +```

[⬆ Back to top](#table-of-contents) -### similarity - -Returns an array of elements that appear in both arrays. - -Use `Array.filter()` to remove values that are not part of `values`, determined using `Array.includes()`. - -```js -const similarity = (arr, values) => arr.filter(v => values.includes(v)); -``` - +### similarity + +Returns an array of elements that appear in both arrays. + +Use `Array.filter()` to remove values that are not part of `values`, determined using `Array.includes()`. + +```js +const similarity = (arr, values) => arr.filter(v => values.includes(v)); +``` +
Examples -```js -similarity([1, 2, 3], [1, 2, 4]); // [1,2] -``` +```js +similarity([1, 2, 3], [1, 2, 4]); // [1,2] +```

[⬆ Back to top](#table-of-contents) -### sortedIndex - -Returns the lowest index at which value should be inserted into array in order to maintain its sort order. - -Check if the array is sorted in descending order (loosely). -Use `Array.findIndex()` to find the appropriate index where the element should be inserted. - -```js -const sortedIndex = (arr, n) => { - const isDescending = arr[0] > arr[arr.length - 1]; - const index = arr.findIndex(el => (isDescending ? n >= el : n <= el)); - return index === -1 ? arr.length : index; -}; -``` - +### sortedIndex + +Returns the lowest index at which value should be inserted into array in order to maintain its sort order. + +Check if the array is sorted in descending order (loosely). +Use `Array.findIndex()` to find the appropriate index where the element should be inserted. + +```js +const sortedIndex = (arr, n) => { + const isDescending = arr[0] > arr[arr.length - 1]; + const index = arr.findIndex(el => (isDescending ? n >= el : n <= el)); + return index === -1 ? arr.length : index; +}; +``` +
Examples -```js -sortedIndex([5, 3, 2, 1], 4); // 1 -sortedIndex([30, 50], 40); // 1 -``` +```js +sortedIndex([5, 3, 2, 1], 4); // 1 +sortedIndex([30, 50], 40); // 1 +```

[⬆ Back to top](#table-of-contents) -### symmetricDifference - -Returns the symmetric difference between two arrays. - -Create a `Set` from each array, then use `Array.filter()` on each of them to only keep values not contained in the other. - -```js -const symmetricDifference = (a, b) => { - const sA = new Set(a), - sB = new Set(b); - return [...a.filter(x => !sB.has(x)), ...b.filter(x => !sA.has(x))]; -}; -``` - +### symmetricDifference + +Returns the symmetric difference between two arrays. + +Create a `Set` from each array, then use `Array.filter()` on each of them to only keep values not contained in the other. + +```js +const symmetricDifference = (a, b) => { + const sA = new Set(a), + sB = new Set(b); + return [...a.filter(x => !sB.has(x)), ...b.filter(x => !sA.has(x))]; +}; +``` +
Examples -```js -symmetricDifference([1, 2, 3], [1, 2, 4]); // [3,4] -``` +```js +symmetricDifference([1, 2, 3], [1, 2, 4]); // [3,4] +```

[⬆ Back to top](#table-of-contents) -### tail - -Returns all elements in an array except for the first one. - -Return `Array.slice(1)` if the array's `length` is more than `1`, otherwise, return the whole array. - -```js -const tail = arr => (arr.length > 1 ? arr.slice(1) : arr); -``` - +### tail + +Returns all elements in an array except for the first one. + +Return `Array.slice(1)` if the array's `length` is more than `1`, otherwise, return the whole array. + +```js +const tail = arr => (arr.length > 1 ? arr.slice(1) : arr); +``` +
Examples -```js -tail([1, 2, 3]); // [2,3] -tail([1]); // [1] -``` +```js +tail([1, 2, 3]); // [2,3] +tail([1]); // [1] +```

[⬆ Back to top](#table-of-contents) -### take - -Returns an array with n elements removed from the beginning. - -Use `Array.slice()` to create a slice of the array with `n` elements taken from the beginning. - -```js -const take = (arr, n = 1) => arr.slice(0, n); -``` - +### take + +Returns an array with n elements removed from the beginning. + +Use `Array.slice()` to create a slice of the array with `n` elements taken from the beginning. + +```js +const take = (arr, n = 1) => arr.slice(0, n); +``` +
Examples -```js -take([1, 2, 3], 5); // [1, 2, 3] -take([1, 2, 3], 0); // [] -``` +```js +take([1, 2, 3], 5); // [1, 2, 3] +take([1, 2, 3], 0); // [] +```

[⬆ Back to top](#table-of-contents) -### takeRight - -Returns an array with n elements removed from the end. - -Use `Array.slice()` to create a slice of the array with `n` elements taken from the end. - -```js -const takeRight = (arr, n = 1) => arr.slice(arr.length - n, arr.length); -``` - +### takeRight + +Returns an array with n elements removed from the end. + +Use `Array.slice()` to create a slice of the array with `n` elements taken from the end. + +```js +const takeRight = (arr, n = 1) => arr.slice(arr.length - n, arr.length); +``` +
Examples -```js -takeRight([1, 2, 3], 2); // [ 2, 3 ] -takeRight([1, 2, 3]); // [3] -``` +```js +takeRight([1, 2, 3], 2); // [ 2, 3 ] +takeRight([1, 2, 3]); // [3] +```

[⬆ Back to top](#table-of-contents) -### union - -Returns every element that exists in any of the two arrays once. - -Create a `Set` with all values of `a` and `b` and convert to an array. - -```js -const union = (a, b) => Array.from(new Set([...a, ...b])); -``` - +### union + +Returns every element that exists in any of the two arrays once. + +Create a `Set` with all values of `a` and `b` and convert to an array. + +```js +const union = (a, b) => Array.from(new Set([...a, ...b])); +``` +
Examples -```js -union([1, 2, 3], [4, 3, 2]); // [1,2,3,4] -``` +```js +union([1, 2, 3], [4, 3, 2]); // [1,2,3,4] +```

[⬆ Back to top](#table-of-contents) -### without - -Filters out the elements of an array, that have one of the specified values. - -Use `Array.filter()` to create an array excluding(using `!Array.includes()`) all given values. - -_(For a snippet that mutates the original array see [`pull`](#pull))_ - -```js -const without = (arr, ...args) => arr.filter(v => !args.includes(v)); -``` - +### without + +Filters out the elements of an array, that have one of the specified values. + +Use `Array.filter()` to create an array excluding(using `!Array.includes()`) all given values. + +_(For a snippet that mutates the original array see [`pull`](#pull))_ + +```js +const without = (arr, ...args) => arr.filter(v => !args.includes(v)); +``` +
Examples -```js -without([2, 1, 2, 3], 1, 2); // [3] -``` +```js +without([2, 1, 2, 3], 1, 2); // [3] +```

[⬆ Back to top](#table-of-contents) -### zip - -Creates an array of elements, grouped based on the position in the original arrays. - -Use `Math.max.apply()` to get the longest array in the arguments. -Creates an array with that length as return value and use `Array.from()` with a map-function to create an array of grouped elements. -If lengths of the argument-arrays vary, `undefined` is used where no value could be found. - -```js -const zip = (...arrays) => { - const maxLength = Math.max(...arrays.map(x => x.length)); - return Array.from({ length: maxLength }).map((_, i) => { - return Array.from({ length: arrays.length }, (_, k) => arrays[k][i]); - }); -}; -``` - +### zip + +Creates an array of elements, grouped based on the position in the original arrays. + +Use `Math.max.apply()` to get the longest array in the arguments. +Creates an array with that length as return value and use `Array.from()` with a map-function to create an array of grouped elements. +If lengths of the argument-arrays vary, `undefined` is used where no value could be found. + +```js +const zip = (...arrays) => { + const maxLength = Math.max(...arrays.map(x => x.length)); + return Array.from({ length: maxLength }).map((_, i) => { + return Array.from({ length: arrays.length }, (_, k) => arrays[k][i]); + }); +}; +``` +
Examples -```js -zip(['a', 'b'], [1, 2], [true, false]); // [['a', 1, true], ['b', 2, false]] -zip(['a'], [1, 2], [true, false]); // [['a', 1, true], [undefined, 2, false]] -``` +```js +zip(['a', 'b'], [1, 2], [true, false]); // [['a', 1, true], ['b', 2, false]] +zip(['a'], [1, 2], [true, false]); // [['a', 1, true], [undefined, 2, false]] +```

[⬆ Back to top](#table-of-contents) -### zipObject - -Given an array of valid property identifiers and an array of values, return an object associating the properties to the values. - -Since an object can have undefined values but not undefined property pointers, the array of properties is used to decide the structure of the resulting object using `Array.reduce()`. - -```js -const zipObject = (props, values) => - props.reduce((obj, prop, index) => ((obj[prop] = values[index]), obj), {}); -``` - +### zipObject + +Given an array of valid property identifiers and an array of values, return an object associating the properties to the values. + +Since an object can have undefined values but not undefined property pointers, the array of properties is used to decide the structure of the resulting object using `Array.reduce()`. + +```js +const zipObject = (props, values) => + props.reduce((obj, prop, index) => ((obj[prop] = values[index]), obj), {}); +``` +
Examples -```js -zipObject(['a', 'b', 'c'], [1, 2]); // {a: 1, b: 2, c: undefined} -zipObject(['a', 'b'], [1, 2, 3]); // {a: 1, b: 2} -``` +```js +zipObject(['a', 'b', 'c'], [1, 2]); // {a: 1, b: 2, c: undefined} +zipObject(['a', 'b'], [1, 2, 3]); // {a: 1, b: 2} +```
@@ -1726,47 +1726,47 @@ zipObject(['a', 'b'], [1, 2, 3]); // {a: 1, b: 2} --- ## 🌐 Browser -### arrayToHtmlList - -Converts the given array elements into `
  • ` tags and appends them to the list of the given id. - -Use `Array.map()` and `document.querySelector()` to create a list of html tags. - -```js -const arrayToHtmlList = (arr, listID) => - arr.map(item => (document.querySelector('#' + listID).innerHTML += `
  • ${item}
    • `)); -``` - +### arrayToHtmlList + +Converts the given array elements into `
  • ` tags and appends them to the list of the given id. + +Use `Array.map()` and `document.querySelector()` to create a list of html tags. + +```js +const arrayToHtmlList = (arr, listID) => + arr.map(item => (document.querySelector('#' + listID).innerHTML += `
  • ${item}
    • `)); +``` +
    Examples -```js -arrayToHtmlList(['item 1', 'item 2'], 'myListID'); -``` +```js +arrayToHtmlList(['item 1', 'item 2'], 'myListID'); +```

    [⬆ Back to top](#table-of-contents) -### bottomVisible - -Returns `true` if the bottom of the page is visible, `false` otherwise. - -Use `scrollY`, `scrollHeight` and `clientHeight` to determine if the bottom of the page is visible. - -```js -const bottomVisible = () => - document.documentElement.clientHeight + window.scrollY >= - (document.documentElement.scrollHeight || document.documentElement.clientHeight); -``` - +### bottomVisible + +Returns `true` if the bottom of the page is visible, `false` otherwise. + +Use `scrollY`, `scrollHeight` and `clientHeight` to determine if the bottom of the page is visible. + +```js +const bottomVisible = () => + document.documentElement.clientHeight + window.scrollY >= + (document.documentElement.scrollHeight || document.documentElement.clientHeight); +``` +
    Examples -```js -bottomVisible(); // true -``` +```js +bottomVisible(); // true +```
    @@ -1815,287 +1815,287 @@ copyToClipboard('Lorem ipsum'); // 'Lorem ipsum' copied to clipboard.
    [⬆ Back to top](#table-of-contents) -### createElement - -Creates an element from a string (without appending it to the document). -If the given string contains multiple elements, only the first one will be returned. - -Use `document.createElement()` to create a new element. -Set its `innerHTML` to the string supplied as the argument. -Use `ParentNode.firstElementChild` to return the element version of the string. - -```js -const createElement = str => { - const el = document.createElement('div'); - el.innerHTML = str; - return el.firstElementChild; -}; -``` - +### createElement + +Creates an element from a string (without appending it to the document). +If the given string contains multiple elements, only the first one will be returned. + +Use `document.createElement()` to create a new element. +Set its `innerHTML` to the string supplied as the argument. +Use `ParentNode.firstElementChild` to return the element version of the string. + +```js +const createElement = str => { + const el = document.createElement('div'); + el.innerHTML = str; + return el.firstElementChild; +}; +``` +
    Examples -```js -const el = createElement( - `
    -

    Hello!

    -
    ` -); -console.log(el.className); // 'container' -``` +```js +const el = createElement( + `
    +

    Hello!

    +
    ` +); +console.log(el.className); // 'container' +```

    [⬆ Back to top](#table-of-contents) -### currentURL - -Returns the current URL. - -Use `window.location.href` to get current URL. - -```js -const currentURL = () => window.location.href; -``` - +### currentURL + +Returns the current URL. + +Use `window.location.href` to get current URL. + +```js +const currentURL = () => window.location.href; +``` +
    Examples -```js -currentURL(); // 'https://google.com' -``` +```js +currentURL(); // 'https://google.com' +```

    [⬆ Back to top](#table-of-contents) -### detectDeviceType - -Detects wether the website is being opened in a mobile device or a desktop/laptop. - -Use a regular expression to test the `navigator.userAgent` property to figure out if the device is a mobile device or a desktop/laptop. - -```js -const detectDeviceType = () => - /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) - ? 'Mobile' - : 'Desktop'; -``` - +### detectDeviceType + +Detects wether the website is being opened in a mobile device or a desktop/laptop. + +Use a regular expression to test the `navigator.userAgent` property to figure out if the device is a mobile device or a desktop/laptop. + +```js +const detectDeviceType = () => + /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) + ? 'Mobile' + : 'Desktop'; +``` +
    Examples -```js -detectDeviceType(); // "Mobile" or "Desktop" -``` +```js +detectDeviceType(); // "Mobile" or "Desktop" +```

    [⬆ Back to top](#table-of-contents) -### elementIsVisibleInViewport - -Returns `true` if the element specified is visible in the viewport, `false` otherwise. - -Use `Element.getBoundingClientRect()` and the `window.inner(Width|Height)` values -to determine if a given element is visible in the viewport. -Omit the second argument to determine if the element is entirely visible, or specify `true` to determine if -it is partially visible. - -```js -const elementIsVisibleInViewport = (el, partiallyVisible = false) => { - const { top, left, bottom, right } = el.getBoundingClientRect(); - const { innerHeight, innerWidth } = window; - return partiallyVisible - ? ((top > 0 && top < innerHeight) || (bottom > 0 && bottom < innerHeight)) && - ((left > 0 && left < innerWidth) || (right > 0 && right < innerWidth)) - : top >= 0 && left >= 0 && bottom <= innerHeight && right <= innerWidth; -}; -``` - +### elementIsVisibleInViewport + +Returns `true` if the element specified is visible in the viewport, `false` otherwise. + +Use `Element.getBoundingClientRect()` and the `window.inner(Width|Height)` values +to determine if a given element is visible in the viewport. +Omit the second argument to determine if the element is entirely visible, or specify `true` to determine if +it is partially visible. + +```js +const elementIsVisibleInViewport = (el, partiallyVisible = false) => { + const { top, left, bottom, right } = el.getBoundingClientRect(); + const { innerHeight, innerWidth } = window; + return partiallyVisible + ? ((top > 0 && top < innerHeight) || (bottom > 0 && bottom < innerHeight)) && + ((left > 0 && left < innerWidth) || (right > 0 && right < innerWidth)) + : top >= 0 && left >= 0 && bottom <= innerHeight && right <= innerWidth; +}; +``` +
    Examples -```js -// e.g. 100x100 viewport and a 10x10px element at position {top: -1, left: 0, bottom: 9, right: 10} -elementIsVisibleInViewport(el); // false - (not fully visible) -elementIsVisibleInViewport(el, true); // true - (partially visible) -``` +```js +// e.g. 100x100 viewport and a 10x10px element at position {top: -1, left: 0, bottom: 9, right: 10} +elementIsVisibleInViewport(el); // false - (not fully visible) +elementIsVisibleInViewport(el, true); // true - (partially visible) +```

    [⬆ Back to top](#table-of-contents) -### getScrollPosition - -Returns the scroll position of the current page. - -Use `pageXOffset` and `pageYOffset` if they are defined, otherwise `scrollLeft` and `scrollTop`. -You can omit `el` to use a default value of `window`. - -```js -const getScrollPosition = (el = window) => ({ - x: el.pageXOffset !== undefined ? el.pageXOffset : el.scrollLeft, - y: el.pageYOffset !== undefined ? el.pageYOffset : el.scrollTop -}); -``` - +### getScrollPosition + +Returns the scroll position of the current page. + +Use `pageXOffset` and `pageYOffset` if they are defined, otherwise `scrollLeft` and `scrollTop`. +You can omit `el` to use a default value of `window`. + +```js +const getScrollPosition = (el = window) => ({ + x: el.pageXOffset !== undefined ? el.pageXOffset : el.scrollLeft, + y: el.pageYOffset !== undefined ? el.pageYOffset : el.scrollTop +}); +``` +
    Examples -```js -getScrollPosition(); // {x: 0, y: 200} -``` +```js +getScrollPosition(); // {x: 0, y: 200} +```

    [⬆ Back to top](#table-of-contents) -### getStyle - -Returns the value of a CSS rule for the specified element. - -Use `Window.getComputedStyle()` to get the value of the CSS rule for the specified element. - -```js -const getStyle = (el, ruleName) => getComputedStyle(el)[ruleName]; -``` - +### getStyle + +Returns the value of a CSS rule for the specified element. + +Use `Window.getComputedStyle()` to get the value of the CSS rule for the specified element. + +```js +const getStyle = (el, ruleName) => getComputedStyle(el)[ruleName]; +``` +
    Examples -```js -getStyle(document.querySelector('p'), 'font-size'); // '16px' -``` +```js +getStyle(document.querySelector('p'), 'font-size'); // '16px' +```

    [⬆ Back to top](#table-of-contents) -### hasClass - -Returns `true` if the element has the specified class, `false` otherwise. - -Use `element.classList.contains()` to check if the element has the specified class. - -```js -const hasClass = (el, className) => el.classList.contains(className); -``` - +### hasClass + +Returns `true` if the element has the specified class, `false` otherwise. + +Use `element.classList.contains()` to check if the element has the specified class. + +```js +const hasClass = (el, className) => el.classList.contains(className); +``` +
    Examples -```js -hasClass(document.querySelector('p.special'), 'special'); // true -``` +```js +hasClass(document.querySelector('p.special'), 'special'); // true +```

    [⬆ Back to top](#table-of-contents) -### hide - -Hides all the elements specified. - -Use the spread operator (`...`) and `Array.forEach()` to apply `display: none` to each element specified. - -```js -const hide = (...el) => [...el].forEach(e => (e.style.display = 'none')); -``` - +### hide + +Hides all the elements specified. + +Use the spread operator (`...`) and `Array.forEach()` to apply `display: none` to each element specified. + +```js +const hide = (...el) => [...el].forEach(e => (e.style.display = 'none')); +``` +
    Examples -```js -hide(document.querySelectorAll('img')); // Hides all elements on the page -``` +```js +hide(document.querySelectorAll('img')); // Hides all elements on the page +```

    [⬆ Back to top](#table-of-contents) -### httpsRedirect - -Redirects the page to HTTPS if its currently in HTTP. Also, pressing the back button doesn't take it back to the HTTP page as its replaced in the history. - -Use `location.protocol` to get the protocol currently being used. If it's not HTTPS, use `location.replace()` to replace the existing page with the HTTPS version of the page. Use `location.href` to get the full address, split it with `String.split()` and remove the protocol part of the URL. - -```js -const httpsRedirect = () => { - if (location.protocol !== 'https:') location.replace('https://' + location.href.split('//')[1]); -}; -``` - +### httpsRedirect + +Redirects the page to HTTPS if its currently in HTTP. Also, pressing the back button doesn't take it back to the HTTP page as its replaced in the history. + +Use `location.protocol` to get the protocol currently being used. If it's not HTTPS, use `location.replace()` to replace the existing page with the HTTPS version of the page. Use `location.href` to get the full address, split it with `String.split()` and remove the protocol part of the URL. + +```js +const httpsRedirect = () => { + if (location.protocol !== 'https:') location.replace('https://' + location.href.split('//')[1]); +}; +``` +
    Examples -```js -httpsRedirect(); // If you are on http://mydomain.com, you are redirected to https://mydomain.com -``` +```js +httpsRedirect(); // If you are on http://mydomain.com, you are redirected to https://mydomain.com +```

    [⬆ Back to top](#table-of-contents) -### off - -Removes an event listener from an element. - -Use `EventTarget.removeEventListener()` to remove an event listener from an element. -Omit the fourth argument `opts` to use `false` or specify it based on the options used when the event listener was added. - -```js -const off = (el, evt, fn, opts = false) => el.removeEventListener(evt, fn, opts); -``` - +### off + +Removes an event listener from an element. + +Use `EventTarget.removeEventListener()` to remove an event listener from an element. +Omit the fourth argument `opts` to use `false` or specify it based on the options used when the event listener was added. + +```js +const off = (el, evt, fn, opts = false) => el.removeEventListener(evt, fn, opts); +``` +
    Examples -```js -const fn = () => console.log('!'); -document.body.addEventListener('click', fn); -off(document.body, 'click', fn); // no longer logs '!' upon clicking on the page -``` +```js +const fn = () => console.log('!'); +document.body.addEventListener('click', fn); +off(document.body, 'click', fn); // no longer logs '!' upon clicking on the page +```

    [⬆ Back to top](#table-of-contents) -### on - -Adds an event listener to an element with the ability to use event delegation. - -Use `EventTarget.addEventListener()` to add an event listener to an element. If there is a `target` property supplied to the options object, ensure the event target matches the target specified and then invoke the callback by supplying the correct `this` context. -Returns a reference to the custom delegator function, in order to be possible to use with [`off`](#off). -Omit `opts` to default to non-delegation behavior and event bubbling. - -```js -const on = (el, evt, fn, opts = {}) => { - const delegatorFn = e => e.target.matches(opts.target) && fn.call(e.target, e); - el.addEventListener(evt, opts.target ? delegatorFn : fn, opts.options || false); - if (opts.target) return delegatorFn; -}; -``` - +### on + +Adds an event listener to an element with the ability to use event delegation. + +Use `EventTarget.addEventListener()` to add an event listener to an element. If there is a `target` property supplied to the options object, ensure the event target matches the target specified and then invoke the callback by supplying the correct `this` context. +Returns a reference to the custom delegator function, in order to be possible to use with [`off`](#off). +Omit `opts` to default to non-delegation behavior and event bubbling. + +```js +const on = (el, evt, fn, opts = {}) => { + const delegatorFn = e => e.target.matches(opts.target) && fn.call(e.target, e); + el.addEventListener(evt, opts.target ? delegatorFn : fn, opts.options || false); + if (opts.target) return delegatorFn; +}; +``` +
    Examples -```js -const fn = () => console.log('!'); -on(document.body, 'click', fn); // logs '!' upon clicking the body -on(document.body, 'click', fn, { target: 'p' }); // logs '!' upon clicking a `p` element child of the body -on(document.body, 'click', fn, { options: true }); // use capturing instead of bubbling -``` +```js +const fn = () => console.log('!'); +on(document.body, 'click', fn); // logs '!' upon clicking the body +on(document.body, 'click', fn, { target: 'p' }); // logs '!' upon clicking a `p` element child of the body +on(document.body, 'click', fn, { options: true }); // use capturing instead of bubbling +```
    @@ -2141,24 +2141,24 @@ onUserInputChange(type => {
    [⬆ Back to top](#table-of-contents) -### redirect - -Redirects to a specified URL. - -Use `window.location.href` or `window.location.replace()` to redirect to `url`. -Pass a second argument to simulate a link click (`true` - default) or an HTTP redirect (`false`). - -```js -const redirect = (url, asLink = true) => - asLink ? (window.location.href = url) : window.location.replace(url); -``` - +### redirect + +Redirects to a specified URL. + +Use `window.location.href` or `window.location.replace()` to redirect to `url`. +Pass a second argument to simulate a link click (`true` - default) or an HTTP redirect (`false`). + +```js +const redirect = (url, asLink = true) => + asLink ? (window.location.href = url) : window.location.replace(url); +``` +
    Examples -```js -redirect('https://google.com'); -``` +```js +redirect('https://google.com'); +```
    @@ -2223,120 +2223,120 @@ runAsync(() => typeof outsideVariable).then(console.log); // 'undefined'
    [⬆ Back to top](#table-of-contents) -### scrollToTop - -Smooth-scrolls to the top of the page. - -Get distance from top using `document.documentElement.scrollTop` or `document.body.scrollTop`. -Scroll by a fraction of the distance from the top. Use `window.requestAnimationFrame()` to animate the scrolling. - -```js -const scrollToTop = () => { - const c = document.documentElement.scrollTop || document.body.scrollTop; - if (c > 0) { - window.requestAnimationFrame(scrollToTop); - window.scrollTo(0, c - c / 8); - } -}; -``` - +### scrollToTop + +Smooth-scrolls to the top of the page. + +Get distance from top using `document.documentElement.scrollTop` or `document.body.scrollTop`. +Scroll by a fraction of the distance from the top. Use `window.requestAnimationFrame()` to animate the scrolling. + +```js +const scrollToTop = () => { + const c = document.documentElement.scrollTop || document.body.scrollTop; + if (c > 0) { + window.requestAnimationFrame(scrollToTop); + window.scrollTo(0, c - c / 8); + } +}; +``` +
    Examples -```js -scrollToTop(); -``` +```js +scrollToTop(); +```

    [⬆ Back to top](#table-of-contents) -### setStyle - -Sets the value of a CSS rule for the specified element. - -Use `element.style` to set the value of the CSS rule for the specified element to `val`. - -```js -const setStyle = (el, ruleName, val) => (el.style[ruleName] = val); -``` - +### setStyle + +Sets the value of a CSS rule for the specified element. + +Use `element.style` to set the value of the CSS rule for the specified element to `val`. + +```js +const setStyle = (el, ruleName, val) => (el.style[ruleName] = val); +``` +
    Examples -```js -setStyle(document.querySelector('p'), 'font-size', '20px'); // The first

    element on the page will have a font-size of 20px -``` +```js +setStyle(document.querySelector('p'), 'font-size', '20px'); // The first

    element on the page will have a font-size of 20px +```


    [⬆ Back to top](#table-of-contents) -### show - -Shows all the elements specified. - -Use the spread operator (`...`) and `Array.forEach()` to clear the `display` property for each element specified. - -```js -const show = (...el) => [...el].forEach(e => (e.style.display = '')); -``` - +### show + +Shows all the elements specified. + +Use the spread operator (`...`) and `Array.forEach()` to clear the `display` property for each element specified. + +```js +const show = (...el) => [...el].forEach(e => (e.style.display = '')); +``` +
    Examples -```js -show(document.querySelectorAll('img')); // Shows all elements on the page -``` +```js +show(document.querySelectorAll('img')); // Shows all elements on the page +```

    [⬆ Back to top](#table-of-contents) -### toggleClass - -Toggle a class for an element. - -Use `element.classList.toggle()` to toggle the specified class for the element. - -```js -const toggleClass = (el, className) => el.classList.toggle(className); -``` - +### toggleClass + +Toggle a class for an element. + +Use `element.classList.toggle()` to toggle the specified class for the element. + +```js +const toggleClass = (el, className) => el.classList.toggle(className); +``` +
    Examples -```js -toggleClass(document.querySelector('p.special'), 'special'); // The paragraph will not have the 'special' class anymore -``` +```js +toggleClass(document.querySelector('p.special'), 'special'); // The paragraph will not have the 'special' class anymore +```

    [⬆ Back to top](#table-of-contents) -### UUIDGeneratorBrowser - -Generates a UUID in a browser. - -Use `crypto` API to generate a UUID, compliant with [RFC4122](https://www.ietf.org/rfc/rfc4122.txt) version 4. - -```js -const UUIDGeneratorBrowser = () => - ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c => - (c ^ (crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (c / 4)))).toString(16) - ); -``` - +### UUIDGeneratorBrowser + +Generates a UUID in a browser. + +Use `crypto` API to generate a UUID, compliant with [RFC4122](https://www.ietf.org/rfc/rfc4122.txt) version 4. + +```js +const UUIDGeneratorBrowser = () => + ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c => + (c ^ (crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (c / 4)))).toString(16) + ); +``` +
    Examples -```js -UUIDGeneratorBrowser(); // '7982fcfe-5721-4632-bede-6000885be57d' -``` +```js +UUIDGeneratorBrowser(); // '7982fcfe-5721-4632-bede-6000885be57d' +```
    @@ -2345,113 +2345,113 @@ UUIDGeneratorBrowser(); // '7982fcfe-5721-4632-bede-6000885be57d' --- ## ⏱️ Date -### formatDuration - -Returns the human readable format of the given number of milliseconds. - -Divide `ms` with the appropriate values to obtain the appropriate values for `day`, `hour`, `minute`, `second` and `millisecond`. -Use `Object.entries()` with `Array.filter()` to keep only non-zero values. -Use `Array.map()` to create the string for each value, pluralizing appropriately. -Use `String.join(', ')` to combine the values into a string. - -```js -const formatDuration = ms => { - if (ms < 0) ms = -ms; - const time = { - day: Math.floor(ms / 86400000), - hour: Math.floor(ms / 3600000) % 24, - minute: Math.floor(ms / 60000) % 60, - second: Math.floor(ms / 1000) % 60, - millisecond: Math.floor(ms) % 1000 - }; - return Object.entries(time) - .filter(val => val[1] !== 0) - .map(val => val[1] + ' ' + (val[1] !== 1 ? val[0] + 's' : val[0])) - .join(', '); -}; -``` - +### formatDuration + +Returns the human readable format of the given number of milliseconds. + +Divide `ms` with the appropriate values to obtain the appropriate values for `day`, `hour`, `minute`, `second` and `millisecond`. +Use `Object.entries()` with `Array.filter()` to keep only non-zero values. +Use `Array.map()` to create the string for each value, pluralizing appropriately. +Use `String.join(', ')` to combine the values into a string. + +```js +const formatDuration = ms => { + if (ms < 0) ms = -ms; + const time = { + day: Math.floor(ms / 86400000), + hour: Math.floor(ms / 3600000) % 24, + minute: Math.floor(ms / 60000) % 60, + second: Math.floor(ms / 1000) % 60, + millisecond: Math.floor(ms) % 1000 + }; + return Object.entries(time) + .filter(val => val[1] !== 0) + .map(val => val[1] + ' ' + (val[1] !== 1 ? val[0] + 's' : val[0])) + .join(', '); +}; +``` +
    Examples -```js -formatDuration(1001); // '1 second, 1 millisecond' -formatDuration(34325055574); // '397 days, 6 hours, 44 minutes, 15 seconds, 574 milliseconds' -``` +```js +formatDuration(1001); // '1 second, 1 millisecond' +formatDuration(34325055574); // '397 days, 6 hours, 44 minutes, 15 seconds, 574 milliseconds' +```

    [⬆ Back to top](#table-of-contents) -### getDaysDiffBetweenDates - -Returns the difference (in days) between two dates. - -Calculate the difference (in days) between two `Date` objects. - -```js -const getDaysDiffBetweenDates = (dateInitial, dateFinal) => - (dateFinal - dateInitial) / (1000 * 3600 * 24); -``` - +### getDaysDiffBetweenDates + +Returns the difference (in days) between two dates. + +Calculate the difference (in days) between two `Date` objects. + +```js +const getDaysDiffBetweenDates = (dateInitial, dateFinal) => + (dateFinal - dateInitial) / (1000 * 3600 * 24); +``` +
    Examples -```js -getDaysDiffBetweenDates(new Date('2017-12-13'), new Date('2017-12-22')); // 9 -``` +```js +getDaysDiffBetweenDates(new Date('2017-12-13'), new Date('2017-12-22')); // 9 +```

    [⬆ Back to top](#table-of-contents) -### toEnglishDate - -Converts a date from American format to English format. - -Use `Date.toISOString()`, `split('T')` and `replace()` to convert a date from American format to the English format. -Throws an error if the passed time cannot be converted to a date. - -```js -const toEnglishDate = time => { - try { - return new Date(time) - .toISOString() - .split('T')[0] - .replace(/-/g, '/'); - } catch (e) {} -}; -``` - +### toEnglishDate + +Converts a date from American format to English format. + +Use `Date.toISOString()`, `split('T')` and `replace()` to convert a date from American format to the English format. +Throws an error if the passed time cannot be converted to a date. + +```js +const toEnglishDate = time => { + try { + return new Date(time) + .toISOString() + .split('T')[0] + .replace(/-/g, '/'); + } catch (e) {} +}; +``` +
    Examples -```js -toEnglishDate('09/21/2010'); // '21/09/2010' -``` +```js +toEnglishDate('09/21/2010'); // '21/09/2010' +```

    [⬆ Back to top](#table-of-contents) -### tomorrow - -Results in a string representation of tomorrow's date. -Use `new Date()` to get today's date, adding `86400000` of seconds to it(24 hours), using `Date.toISOString()` to convert Date object to string. - -```js -const tomorrow = () => new Date(new Date().getTime() + 86400000).toISOString().split('T')[0]; -``` - +### tomorrow + +Results in a string representation of tomorrow's date. +Use `new Date()` to get today's date, adding `86400000` of seconds to it(24 hours), using `Date.toISOString()` to convert Date object to string. + +```js +const tomorrow = () => new Date(new Date().getTime() + 86400000).toISOString().split('T')[0]; +``` +
    Examples -```js -tomorrow(); // 2017-12-27 (if current date is 2017-12-26) -``` +```js +tomorrow(); // 2017-12-27 (if current date is 2017-12-26) +```
    @@ -2460,254 +2460,254 @@ tomorrow(); // 2017-12-27 (if current date is 2017-12-26) --- ## 🎛️ Function -### chainAsync - -Chains asynchronous functions. - -Loop through an array of functions containing asynchronous events, calling `next` when each asynchronous event has completed. - -```js -const chainAsync = fns => { - let curr = 0; - const next = () => fns[curr++](next); - next(); -}; -``` - +### chainAsync + +Chains asynchronous functions. + +Loop through an array of functions containing asynchronous events, calling `next` when each asynchronous event has completed. + +```js +const chainAsync = fns => { + let curr = 0; + const next = () => fns[curr++](next); + next(); +}; +``` +
    Examples -```js -chainAsync([ - next => { - console.log('0 seconds'); - setTimeout(next, 1000); - }, - next => { - console.log('1 second'); - } -]); -``` +```js +chainAsync([ + next => { + console.log('0 seconds'); + setTimeout(next, 1000); + }, + next => { + console.log('1 second'); + } +]); +```

    [⬆ Back to top](#table-of-contents) -### compose - -Performs right-to-left function composition. - -Use `Array.reduce()` to perform right-to-left function composition. -The last (rightmost) function can accept one or more arguments; the remaining functions must be unary. - -```js -const compose = (...fns) => fns.reduce((f, g) => (...args) => f(g(...args))); -``` - +### compose + +Performs right-to-left function composition. + +Use `Array.reduce()` to perform right-to-left function composition. +The last (rightmost) function can accept one or more arguments; the remaining functions must be unary. + +```js +const compose = (...fns) => fns.reduce((f, g) => (...args) => f(g(...args))); +``` +
    Examples -```js -const add5 = x => x + 5; -const multiply = (x, y) => x * y; -const multiplyAndAdd5 = compose(add5, multiply); -multiplyAndAdd5(5, 2); // 15 -``` +```js +const add5 = x => x + 5; +const multiply = (x, y) => x * y; +const multiplyAndAdd5 = compose(add5, multiply); +multiplyAndAdd5(5, 2); // 15 +```

    [⬆ Back to top](#table-of-contents) -### curry - -Curries a function. - -Use recursion. -If the number of provided arguments (`args`) is sufficient, call the passed function `fn`. -Otherwise, return a curried function `fn` that expects the rest of the arguments. -If you want to curry a function that accepts a variable number of arguments (a variadic function, e.g. `Math.min()`), you can optionally pass the number of arguments to the second parameter `arity`. - -```js -const curry = (fn, arity = fn.length, ...args) => - arity <= args.length ? fn(...args) : curry.bind(null, fn, arity, ...args); -``` - +### curry + +Curries a function. + +Use recursion. +If the number of provided arguments (`args`) is sufficient, call the passed function `fn`. +Otherwise, return a curried function `fn` that expects the rest of the arguments. +If you want to curry a function that accepts a variable number of arguments (a variadic function, e.g. `Math.min()`), you can optionally pass the number of arguments to the second parameter `arity`. + +```js +const curry = (fn, arity = fn.length, ...args) => + arity <= args.length ? fn(...args) : curry.bind(null, fn, arity, ...args); +``` +
    Examples -```js -curry(Math.pow)(2)(10); // 1024 -curry(Math.min, 3)(10)(50)(2); // 2 -``` +```js +curry(Math.pow)(2)(10); // 1024 +curry(Math.min, 3)(10)(50)(2); // 2 +```

    [⬆ Back to top](#table-of-contents) -### defer - -Defers invoking a function until the current call stack has cleared. - -Use `setTimeout()` with a timeout of 1ms to add a new event to the browser event queue and allow the rendering engine to complete its work. Use the spread (`...`) operator to supply the function with an arbitrary number of arguments. - -```js -const defer = (fn, ...args) => setTimeout(fn, 1, ...args); -``` - +### defer + +Defers invoking a function until the current call stack has cleared. + +Use `setTimeout()` with a timeout of 1ms to add a new event to the browser event queue and allow the rendering engine to complete its work. Use the spread (`...`) operator to supply the function with an arbitrary number of arguments. + +```js +const defer = (fn, ...args) => setTimeout(fn, 1, ...args); +``` +
    Examples -```js -// Example A: -defer(console.log, 'a'), console.log('b'); // logs 'b' then 'a' - -// Example B: -document.querySelector('#someElement').innerHTML = 'Hello'; -longRunningFunction(); //Browser will not update the HTML until this has finished -defer(longRunningFunction); // Browser will update the HTML then run the function -``` +```js +// Example A: +defer(console.log, 'a'), console.log('b'); // logs 'b' then 'a' + +// Example B: +document.querySelector('#someElement').innerHTML = 'Hello'; +longRunningFunction(); //Browser will not update the HTML until this has finished +defer(longRunningFunction); // Browser will update the HTML then run the function +```

    [⬆ Back to top](#table-of-contents) -### functionName - -Logs the name of a function. - -Use `console.debug()` and the `name` property of the passed method to log the method's name to the `debug` channel of the console. - -```js -const functionName = fn => (console.debug(fn.name), fn); -``` - +### functionName + +Logs the name of a function. + +Use `console.debug()` and the `name` property of the passed method to log the method's name to the `debug` channel of the console. + +```js +const functionName = fn => (console.debug(fn.name), fn); +``` +
    Examples -```js -functionName(Math.max); // max (logged in debug channel of console) -``` +```js +functionName(Math.max); // max (logged in debug channel of console) +```

    [⬆ Back to top](#table-of-contents) -### memoize - -Returns the memoized (cached) function. - -Create an empty cache by instantiating a new `Map` object. -Return a function which takes a single argument to be supplied to the memoized function by first checking if the function's output for that specific input value is already cached, or store and return it if not. The `function` keyword must be used in order to allow the memoized function to have its `this` context changed if necessary. -Allow access to the `cache` by setting it as a property on the returned function. - -```js -const memoize = fn => { - const cache = new Map(); - const cached = function(val) { - return cache.has(val) ? cache.get(val) : cache.set(val, fn.call(this, val)) && cache.get(val); - }; - cached.cache = cache; - return cached; -}; -``` - +### memoize + +Returns the memoized (cached) function. + +Create an empty cache by instantiating a new `Map` object. +Return a function which takes a single argument to be supplied to the memoized function by first checking if the function's output for that specific input value is already cached, or store and return it if not. The `function` keyword must be used in order to allow the memoized function to have its `this` context changed if necessary. +Allow access to the `cache` by setting it as a property on the returned function. + +```js +const memoize = fn => { + const cache = new Map(); + const cached = function(val) { + return cache.has(val) ? cache.get(val) : cache.set(val, fn.call(this, val)) && cache.get(val); + }; + cached.cache = cache; + return cached; +}; +``` +
    Examples -```js -// See the `anagrams` snippet. -const anagramsCached = memoize(anagrams); -anagramsCached('javascript'); // takes a long time -anagramsCached('javascript'); // returns virtually instantly since it's now cached -console.log(anagramsCached.cache); // The cached anagrams map -``` +```js +// See the `anagrams` snippet. +const anagramsCached = memoize(anagrams); +anagramsCached('javascript'); // takes a long time +anagramsCached('javascript'); // returns virtually instantly since it's now cached +console.log(anagramsCached.cache); // The cached anagrams map +```

    [⬆ Back to top](#table-of-contents) -### once - -Ensures a function is called only once. - -Utilizing a closure, use a flag, `called`, and set it to `true` once the function is called for the first time, preventing it from being called again. In order to allow the function to have its `this` context changed (such as in an event listener), the `function` keyword must be used, and the supplied function must have the context applied. -Allow the function to be supplied with an arbitrary number of arguments using the rest/spread (`...`) operator. - -```js -const once = fn => { - let called = false; - return function(...args) { - if (called) return; - called = true; - return fn.apply(this, args); - }; -}; -``` - +### once + +Ensures a function is called only once. + +Utilizing a closure, use a flag, `called`, and set it to `true` once the function is called for the first time, preventing it from being called again. In order to allow the function to have its `this` context changed (such as in an event listener), the `function` keyword must be used, and the supplied function must have the context applied. +Allow the function to be supplied with an arbitrary number of arguments using the rest/spread (`...`) operator. + +```js +const once = fn => { + let called = false; + return function(...args) { + if (called) return; + called = true; + return fn.apply(this, args); + }; +}; +``` +
    Examples -```js -const startApp = function(event) { - console.log(this, event); // document.body, MouseEvent -}; -document.body.addEventListener('click', once(startApp)); // only runs `startApp` once upon click -``` +```js +const startApp = function(event) { + console.log(this, event); // document.body, MouseEvent +}; +document.body.addEventListener('click', once(startApp)); // only runs `startApp` once upon click +```

    [⬆ Back to top](#table-of-contents) -### runPromisesInSeries - -Runs an array of promises in series. - -Use `Array.reduce()` to create a promise chain, where each promise returns the next promise when resolved. - -```js -const runPromisesInSeries = ps => ps.reduce((p, next) => p.then(next), Promise.resolve()); -``` - +### runPromisesInSeries + +Runs an array of promises in series. + +Use `Array.reduce()` to create a promise chain, where each promise returns the next promise when resolved. + +```js +const runPromisesInSeries = ps => ps.reduce((p, next) => p.then(next), Promise.resolve()); +``` +
    Examples -```js -const delay = d => new Promise(r => setTimeout(r, d)); -runPromisesInSeries([() => delay(1000), () => delay(2000)]); // Executes each promise sequentially, taking a total of 3 seconds to complete -``` +```js +const delay = d => new Promise(r => setTimeout(r, d)); +runPromisesInSeries([() => delay(1000), () => delay(2000)]); // Executes each promise sequentially, taking a total of 3 seconds to complete +```

    [⬆ Back to top](#table-of-contents) -### sleep - -Delays the execution of an asynchronous function. - -Delay executing part of an `async` function, by putting it to sleep, returning a `Promise`. - -```js -const sleep = ms => new Promise(resolve => setTimeout(resolve, ms)); -``` - +### sleep + +Delays the execution of an asynchronous function. + +Delay executing part of an `async` function, by putting it to sleep, returning a `Promise`. + +```js +const sleep = ms => new Promise(resolve => setTimeout(resolve, ms)); +``` +
    Examples -```js -async function sleepyWork() { - console.log("I'm going to sleep for 1 second."); - await sleep(1000); - console.log('I woke up after 1 second.'); -} -``` +```js +async function sleepyWork() { + console.log("I'm going to sleep for 1 second."); + await sleep(1000); + console.log('I woke up after 1 second.'); +} +```
    @@ -2716,23 +2716,23 @@ async function sleepyWork() { --- ## 🔮 Logic -### negate - -Negates a predicate function. - -Take a predicate function and apply the not operator (`!`) to it with its arguments. - -```js -const negate = func => (...args) => !func(...args); -``` - +### negate + +Negates a predicate function. + +Take a predicate function and apply the not operator (`!`) to it with its arguments. + +```js +const negate = func => (...args) => !func(...args); +``` +
    Examples -```js -filter([1, 2, 3, 4, 5, 6], negate(isEven)); // [1, 3, 5] -negate(isOdd)(1); // false -``` +```js +filter([1, 2, 3, 4, 5, 6], negate(isEven)); // [1, 3, 5] +negate(isOdd)(1); // false +```
    @@ -2741,92 +2741,92 @@ negate(isOdd)(1); // false --- ## ➗ Math -### average - -Returns the average of an of two or more numbers. - -Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`, divide by the `length` of the array. - -```js -const average = (...nums) => [...nums].reduce((acc, val) => acc + val, 0) / nums.length; -``` - +### average + +Returns the average of an of two or more numbers. + +Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`, divide by the `length` of the array. + +```js +const average = (...nums) => [...nums].reduce((acc, val) => acc + val, 0) / nums.length; +``` +
    Examples -```js -average(...[1, 2, 3]); // 2 -average(1, 2, 3); // 2 -``` +```js +average(...[1, 2, 3]); // 2 +average(1, 2, 3); // 2 +```

    [⬆ Back to top](#table-of-contents) -### clampNumber - -Clamps `num` within the inclusive range specified by the boundary values `a` and `b`. - -If `num` falls within the range, return `num`. -Otherwise, return the nearest number in the range. - -```js -const clampNumber = (num, a, b) => Math.max(Math.min(num, Math.max(a, b)), Math.min(a, b)); -``` - +### clampNumber + +Clamps `num` within the inclusive range specified by the boundary values `a` and `b`. + +If `num` falls within the range, return `num`. +Otherwise, return the nearest number in the range. + +```js +const clampNumber = (num, a, b) => Math.max(Math.min(num, Math.max(a, b)), Math.min(a, b)); +``` +
    Examples -```js -clampNumber(2, 3, 5); // 3 -clampNumber(1, -1, -5); // -1 -``` +```js +clampNumber(2, 3, 5); // 3 +clampNumber(1, -1, -5); // -1 +```

    [⬆ Back to top](#table-of-contents) -### digitize - -Converts a number to an array of digits. - -Convert the number to a string, using the spread operator (`...`) to build an array. -Use `Array.map()` and `parseInt()` to transform each value to an integer. - -```js -const digitize = n => [...`${n}`].map(i => parseInt(i)); -``` - +### digitize + +Converts a number to an array of digits. + +Convert the number to a string, using the spread operator (`...`) to build an array. +Use `Array.map()` and `parseInt()` to transform each value to an integer. + +```js +const digitize = n => [...`${n}`].map(i => parseInt(i)); +``` +
    Examples -```js -digitize(123); // [1, 2, 3] -``` +```js +digitize(123); // [1, 2, 3] +```

    [⬆ Back to top](#table-of-contents) -### distance - -Returns the distance between two points. - -Use `Math.hypot()` to calculate the Euclidean distance between two points. - -```js -const distance = (x0, y0, x1, y1) => Math.hypot(x1 - x0, y1 - y0); -``` - +### distance + +Returns the distance between two points. + +Use `Math.hypot()` to calculate the Euclidean distance between two points. + +```js +const distance = (x0, y0, x1, y1) => Math.hypot(x1 - x0, y1 - y0); +``` +
    Examples -```js -distance(1, 1, 2, 3); // 2.23606797749979 -``` +```js +distance(1, 1, 2, 3); // 2.23606797749979 +```
    @@ -2886,583 +2886,583 @@ own individual rating by supplying it as the third argument.
    [⬆ Back to top](#table-of-contents) -### factorial - -Calculates the factorial of a number. - -Use recursion. -If `n` is less than or equal to `1`, return `1`. -Otherwise, return the product of `n` and the factorial of `n - 1`. -Throws an exception if `n` is a negative number. - -```js -const factorial = n => - n < 0 - ? (() => { - throw new TypeError('Negative numbers are not allowed!'); - })() - : n <= 1 ? 1 : n * factorial(n - 1); -``` - +### factorial + +Calculates the factorial of a number. + +Use recursion. +If `n` is less than or equal to `1`, return `1`. +Otherwise, return the product of `n` and the factorial of `n - 1`. +Throws an exception if `n` is a negative number. + +```js +const factorial = n => + n < 0 + ? (() => { + throw new TypeError('Negative numbers are not allowed!'); + })() + : n <= 1 ? 1 : n * factorial(n - 1); +``` +
    Examples -```js -factorial(6); // 720 -``` +```js +factorial(6); // 720 +```

    [⬆ Back to top](#table-of-contents) -### fibonacci - -Generates an array, containing the Fibonacci sequence, up until the nth term. - -Create an empty array of the specific length, initializing the first two values (`0` and `1`). -Use `Array.reduce()` to add values into the array, using the sum of the last two values, except for the first two. - -```js -const fibonacci = n => - Array.from({ length: n }).reduce( - (acc, val, i) => acc.concat(i > 1 ? acc[i - 1] + acc[i - 2] : i), - [] - ); -``` - +### fibonacci + +Generates an array, containing the Fibonacci sequence, up until the nth term. + +Create an empty array of the specific length, initializing the first two values (`0` and `1`). +Use `Array.reduce()` to add values into the array, using the sum of the last two values, except for the first two. + +```js +const fibonacci = n => + Array.from({ length: n }).reduce( + (acc, val, i) => acc.concat(i > 1 ? acc[i - 1] + acc[i - 2] : i), + [] + ); +``` +
    Examples -```js -fibonacci(6); // [0, 1, 1, 2, 3, 5] -``` +```js +fibonacci(6); // [0, 1, 1, 2, 3, 5] +```

    [⬆ Back to top](#table-of-contents) -### gcd - -Calculates the greatest common divisor between two or more numbers/arrays. - -The inner `_gcd` function uses recursion. -Base case is when `y` equals `0`. In this case, return `x`. -Otherwise, return the GCD of `y` and the remainder of the division `x/y`. - -```js -const gcd = (...arr) => { - const _gcd = (x, y) => (!y ? x : gcd(y, x % y)); - return [...arr].reduce((a, b) => _gcd(a, b)); -}; -``` - +### gcd + +Calculates the greatest common divisor between two or more numbers/arrays. + +The inner `_gcd` function uses recursion. +Base case is when `y` equals `0`. In this case, return `x`. +Otherwise, return the GCD of `y` and the remainder of the division `x/y`. + +```js +const gcd = (...arr) => { + const _gcd = (x, y) => (!y ? x : gcd(y, x % y)); + return [...arr].reduce((a, b) => _gcd(a, b)); +}; +``` +
    Examples -```js -gcd(8, 36); // 4 -gcd(...[12, 8, 32]); // 4 -``` +```js +gcd(8, 36); // 4 +gcd(...[12, 8, 32]); // 4 +```

    [⬆ Back to top](#table-of-contents) -### geometricProgression - -Initializes an array containing the numbers in the specified range where `start` and `end` are inclusive and the ratio between two terms is `step`. -Returns an error if `step` equals `1`. - -Use `Array.from()`, `Math.log()` and `Math.floor()` to create an array of the desired length, `Array.map()` to fill with the desired values in a range. -Omit the second argument, `start`, to use a default value of `1`. -Omit the third argument, `step`, to use a default value of `2`. - -```js -const geometricProgression = (end, start = 1, step = 2) => - Array.from({ length: Math.floor(Math.log(end / start) / Math.log(step)) + 1 }).map( - (v, i) => start * step ** i - ); -``` - +### geometricProgression + +Initializes an array containing the numbers in the specified range where `start` and `end` are inclusive and the ratio between two terms is `step`. +Returns an error if `step` equals `1`. + +Use `Array.from()`, `Math.log()` and `Math.floor()` to create an array of the desired length, `Array.map()` to fill with the desired values in a range. +Omit the second argument, `start`, to use a default value of `1`. +Omit the third argument, `step`, to use a default value of `2`. + +```js +const geometricProgression = (end, start = 1, step = 2) => + Array.from({ length: Math.floor(Math.log(end / start) / Math.log(step)) + 1 }).map( + (v, i) => start * step ** i + ); +``` +
    Examples -```js -geometricProgression(256); // [1, 2, 4, 8, 16, 32, 64, 128, 256] -geometricProgression(256, 3); // [3, 6, 12, 24, 48, 96, 192] -geometricProgression(256, 1, 4); // [1, 4, 16, 64, 256] -``` +```js +geometricProgression(256); // [1, 2, 4, 8, 16, 32, 64, 128, 256] +geometricProgression(256, 3); // [3, 6, 12, 24, 48, 96, 192] +geometricProgression(256, 1, 4); // [1, 4, 16, 64, 256] +```

    [⬆ Back to top](#table-of-contents) -### hammingDistance - -Calculates the Hamming distance between two values. - -Use XOR operator (`^`) to find the bit difference between the two numbers, convert to a binary string using `toString(2)`. -Count and return the number of `1`s in the string, using `match(/1/g)`. - -```js -const hammingDistance = (num1, num2) => ((num1 ^ num2).toString(2).match(/1/g) || '').length; -``` - +### hammingDistance + +Calculates the Hamming distance between two values. + +Use XOR operator (`^`) to find the bit difference between the two numbers, convert to a binary string using `toString(2)`. +Count and return the number of `1`s in the string, using `match(/1/g)`. + +```js +const hammingDistance = (num1, num2) => ((num1 ^ num2).toString(2).match(/1/g) || '').length; +``` +
    Examples -```js -hammingDistance(2, 3); // 1 -``` +```js +hammingDistance(2, 3); // 1 +```

    [⬆ Back to top](#table-of-contents) -### inRange - -Checks if the given number falls within the given range. - -Use arithmetic comparison to check if the given number is in the specified range. -If the second parameter, `end`, is not specified, the range is considered to be from `0` to `start`. - -```js -const inRange = (n, start, end = null) => { - if (end && start > end) end = [start, (start = end)][0]; - return end == null ? n >= 0 && n < start : n >= start && n < end; -}; -``` - +### inRange + +Checks if the given number falls within the given range. + +Use arithmetic comparison to check if the given number is in the specified range. +If the second parameter, `end`, is not specified, the range is considered to be from `0` to `start`. + +```js +const inRange = (n, start, end = null) => { + if (end && start > end) end = [start, (start = end)][0]; + return end == null ? n >= 0 && n < start : n >= start && n < end; +}; +``` +
    Examples -```js -inRange(3, 2, 5); // true -inRange(3, 4); // true -inRange(2, 3, 5); // false -inrange(3, 2); // false -``` +```js +inRange(3, 2, 5); // true +inRange(3, 4); // true +inRange(2, 3, 5); // false +inrange(3, 2); // false +```

    [⬆ Back to top](#table-of-contents) -### isDivisible - -Checks if the first numeric argument is divisible by the second one. - -Use the modulo operator (`%`) to check if the remainder is equal to `0`. - -```js -const isDivisible = (dividend, divisor) => dividend % divisor === 0; -``` - +### isDivisible + +Checks if the first numeric argument is divisible by the second one. + +Use the modulo operator (`%`) to check if the remainder is equal to `0`. + +```js +const isDivisible = (dividend, divisor) => dividend % divisor === 0; +``` +
    Examples -```js -isDivisible(6, 3); // true -``` +```js +isDivisible(6, 3); // true +```

    [⬆ Back to top](#table-of-contents) -### isEven - -Returns `true` if the given number is even, `false` otherwise. - -Checks whether a number is odd or even using the modulo (`%`) operator. -Returns `true` if the number is even, `false` if the number is odd. - -```js -const isEven = num => num % 2 === 0; -``` - +### isEven + +Returns `true` if the given number is even, `false` otherwise. + +Checks whether a number is odd or even using the modulo (`%`) operator. +Returns `true` if the number is even, `false` if the number is odd. + +```js +const isEven = num => num % 2 === 0; +``` +
    Examples -```js -isEven(3); // false -``` +```js +isEven(3); // false +```

    [⬆ Back to top](#table-of-contents) -### isPrime - -Checks if the provided integer is a prime number. - -Check numbers from `2` to the square root of the given number. -Return `false` if any of them divides the given number, else return `true`, unless the number is less than `2`. - -```js -const isPrime = num => { - const boundary = Math.floor(Math.sqrt(num)); - for (var i = 2; i <= boundary; i++) if (num % i == 0) return false; - return num >= 2; -}; -``` - +### isPrime + +Checks if the provided integer is a prime number. + +Check numbers from `2` to the square root of the given number. +Return `false` if any of them divides the given number, else return `true`, unless the number is less than `2`. + +```js +const isPrime = num => { + const boundary = Math.floor(Math.sqrt(num)); + for (var i = 2; i <= boundary; i++) if (num % i == 0) return false; + return num >= 2; +}; +``` +
    Examples -```js -isPrime(11); // true -``` +```js +isPrime(11); // true +```

    [⬆ Back to top](#table-of-contents) -### lcm - -Returns the least common multiple of two or more numbers. - -Use the greatest common divisor (GCD) formula and `Math.abs()` to determine the least common multiple. -The GCD formula uses recursion. - -```js -const lcm = (...arr) => { - const gcd = (x, y) => (!y ? x : gcd(y, x % y)); - const _lcm = (x, y) => x * y / gcd(x, y); - return [...arr].reduce((a, b) => _lcm(a, b)); -}; -``` - +### lcm + +Returns the least common multiple of two or more numbers. + +Use the greatest common divisor (GCD) formula and `Math.abs()` to determine the least common multiple. +The GCD formula uses recursion. + +```js +const lcm = (...arr) => { + const gcd = (x, y) => (!y ? x : gcd(y, x % y)); + const _lcm = (x, y) => x * y / gcd(x, y); + return [...arr].reduce((a, b) => _lcm(a, b)); +}; +``` +
    Examples -```js -lcm(12, 7); // 84 -lcm(...[1, 3, 4, 5]); // 60 -``` +```js +lcm(12, 7); // 84 +lcm(...[1, 3, 4, 5]); // 60 +```

    [⬆ Back to top](#table-of-contents) -### luhnCheck - -Implementation of the [Luhn Algorithm](https://en.wikipedia.org/wiki/Luhn_algorithm) used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, National Provider Identifier numbers etc. - -Use `String.split('')`, `Array.reverse()` and `Array.map()` in combination with `parseInt()` to obtain an array of digits. -Use `Array.splice(0,1)` to obtain the last digit. -Use `Array.reduce()` to implement the Luhn Algorithm. -Return `true` if `sum` is divisible by `10`, `false` otherwise. - - -```js -const luhnCheck = num => { - let arr = (num + '') - .split('') - .reverse() - .map(x => parseInt(x)); - let lastDigit = arr.splice(0, 1)[0]; - let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + (val * 2) % 9 || 9), 0); - sum += lastDigit; - return sum % 10 === 0; -}; -``` - +### luhnCheck + +Implementation of the [Luhn Algorithm](https://en.wikipedia.org/wiki/Luhn_algorithm) used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, National Provider Identifier numbers etc. + +Use `String.split('')`, `Array.reverse()` and `Array.map()` in combination with `parseInt()` to obtain an array of digits. +Use `Array.splice(0,1)` to obtain the last digit. +Use `Array.reduce()` to implement the Luhn Algorithm. +Return `true` if `sum` is divisible by `10`, `false` otherwise. + + +```js +const luhnCheck = num => { + let arr = (num + '') + .split('') + .reverse() + .map(x => parseInt(x)); + let lastDigit = arr.splice(0, 1)[0]; + let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + (val * 2) % 9 || 9), 0); + sum += lastDigit; + return sum % 10 === 0; +}; +``` +
    Examples -```js -luhnCheck('4485275742308327'); // true -luhnCheck(6011329933655299); // true -luhnCheck(123456789); // false -``` +```js +luhnCheck('4485275742308327'); // true +luhnCheck(6011329933655299); // true +luhnCheck(123456789); // false +```

    [⬆ Back to top](#table-of-contents) -### median - -Returns the median of an array of numbers. - -Find the middle of the array, use `Array.sort()` to sort the values. -Return the number at the midpoint if `length` is odd, otherwise the average of the two middle numbers. - -```js -const median = arr => { - const mid = Math.floor(arr.length / 2), - nums = [...arr].sort((a, b) => a - b); - return arr.length % 2 !== 0 ? nums[mid] : (nums[mid - 1] + nums[mid]) / 2; -}; -``` - +### median + +Returns the median of an array of numbers. + +Find the middle of the array, use `Array.sort()` to sort the values. +Return the number at the midpoint if `length` is odd, otherwise the average of the two middle numbers. + +```js +const median = arr => { + const mid = Math.floor(arr.length / 2), + nums = [...arr].sort((a, b) => a - b); + return arr.length % 2 !== 0 ? nums[mid] : (nums[mid - 1] + nums[mid]) / 2; +}; +``` +
    Examples -```js -median([5, 6, 50, 1, -5]); // 5 -``` +```js +median([5, 6, 50, 1, -5]); // 5 +```

    [⬆ Back to top](#table-of-contents) -### percentile - -Uses the percentile formula to calculate how many numbers in the given array are less or equal to the given value. - -Use `Array.reduce()` to calculate how many numbers are below the value and how many are the same value and apply the percentile formula. - -```js -const percentile = (arr, val) => - 100 * arr.reduce((acc, v) => acc + (v < val ? 1 : 0) + (v === val ? 0.5 : 0), 0) / arr.length; -``` - +### percentile + +Uses the percentile formula to calculate how many numbers in the given array are less or equal to the given value. + +Use `Array.reduce()` to calculate how many numbers are below the value and how many are the same value and apply the percentile formula. + +```js +const percentile = (arr, val) => + 100 * arr.reduce((acc, v) => acc + (v < val ? 1 : 0) + (v === val ? 0.5 : 0), 0) / arr.length; +``` +
    Examples -```js -percentile([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 6); // 55 -``` +```js +percentile([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 6); // 55 +```

    [⬆ Back to top](#table-of-contents) -### powerset - -Returns the powerset of a given array of numbers. - -Use `Array.reduce()` combined with `Array.map()` to iterate over elements and combine into an array containing all combinations. - -```js -const powerset = arr => arr.reduce((a, v) => a.concat(a.map(r => [v].concat(r))), [[]]); -``` - +### powerset + +Returns the powerset of a given array of numbers. + +Use `Array.reduce()` combined with `Array.map()` to iterate over elements and combine into an array containing all combinations. + +```js +const powerset = arr => arr.reduce((a, v) => a.concat(a.map(r => [v].concat(r))), [[]]); +``` +
    Examples -```js -powerset([1, 2]); // [[], [1], [2], [2,1]] -``` +```js +powerset([1, 2]); // [[], [1], [2], [2,1]] +```

    [⬆ Back to top](#table-of-contents) -### primes - -Generates primes up to a given number, using the Sieve of Eratosthenes. - -Generate an array from `2` to the given number. Use `Array.filter()` to filter out the values divisible by any number from `2` to the square root of the provided number. - -```js -const primes = num => { - let arr = Array.from({ length: num - 1 }).map((x, i) => i + 2), - sqroot = Math.floor(Math.sqrt(num)), - numsTillSqroot = Array.from({ length: sqroot - 1 }).map((x, i) => i + 2); - numsTillSqroot.forEach(x => (arr = arr.filter(y => y % x !== 0 || y == x))); - return arr; -}; -``` - +### primes + +Generates primes up to a given number, using the Sieve of Eratosthenes. + +Generate an array from `2` to the given number. Use `Array.filter()` to filter out the values divisible by any number from `2` to the square root of the provided number. + +```js +const primes = num => { + let arr = Array.from({ length: num - 1 }).map((x, i) => i + 2), + sqroot = Math.floor(Math.sqrt(num)), + numsTillSqroot = Array.from({ length: sqroot - 1 }).map((x, i) => i + 2); + numsTillSqroot.forEach(x => (arr = arr.filter(y => y % x !== 0 || y == x))); + return arr; +}; +``` +
    Examples -```js -primes(10); // [2,3,5,7] -``` +```js +primes(10); // [2,3,5,7] +```

    [⬆ Back to top](#table-of-contents) -### randomIntegerInRange - -Returns a random integer in the specified range. - -Use `Math.random()` to generate a random number and map it to the desired range, using `Math.floor()` to make it an integer. - -```js -const randomIntegerInRange = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min; -``` - +### randomIntegerInRange + +Returns a random integer in the specified range. + +Use `Math.random()` to generate a random number and map it to the desired range, using `Math.floor()` to make it an integer. + +```js +const randomIntegerInRange = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min; +``` +
    Examples -```js -randomIntegerInRange(0, 5); // 2 -``` +```js +randomIntegerInRange(0, 5); // 2 +```

    [⬆ Back to top](#table-of-contents) -### randomNumberInRange - -Returns a random number in the specified range. - -Use `Math.random()` to generate a random value, map it to the desired range using multiplication. - -```js -const randomNumberInRange = (min, max) => Math.random() * (max - min) + min; -``` - +### randomNumberInRange + +Returns a random number in the specified range. + +Use `Math.random()` to generate a random value, map it to the desired range using multiplication. + +```js +const randomNumberInRange = (min, max) => Math.random() * (max - min) + min; +``` +
    Examples -```js -randomNumberInRange(2, 10); // 6.0211363285087005 -``` +```js +randomNumberInRange(2, 10); // 6.0211363285087005 +```

    [⬆ Back to top](#table-of-contents) -### round - -Rounds a number to a specified amount of digits. - -Use `Math.round()` and template literals to round the number to the specified number of digits. -Omit the second argument, `decimals` to round to an integer. - -```js -const round = (n, decimals = 0) => Number(`${Math.round(`${n}e${decimals}`)}e-${decimals}`); -``` - +### round + +Rounds a number to a specified amount of digits. + +Use `Math.round()` and template literals to round the number to the specified number of digits. +Omit the second argument, `decimals` to round to an integer. + +```js +const round = (n, decimals = 0) => Number(`${Math.round(`${n}e${decimals}`)}e-${decimals}`); +``` +
    Examples -```js -round(1.005, 2); // 1.01 -``` +```js +round(1.005, 2); // 1.01 +```

    [⬆ Back to top](#table-of-contents) -### sbdm - -Hashes the input string into a whole number. - -Use `String.split('')` and `Array.reduce()` to create a hash of the input string, utilizing bit shifting. - -```js -const sdbm = str => { - let arr = str.split(''); - return arr.reduce( - (hashCode, currentVal) => - (hashCode = currentVal.charCodeAt(0) + (hashCode << 6) + (hashCode << 16) - hashCode), - 0 - ); -}; -``` - +### sbdm + +Hashes the input string into a whole number. + +Use `String.split('')` and `Array.reduce()` to create a hash of the input string, utilizing bit shifting. + +```js +const sdbm = str => { + let arr = str.split(''); + return arr.reduce( + (hashCode, currentVal) => + (hashCode = currentVal.charCodeAt(0) + (hashCode << 6) + (hashCode << 16) - hashCode), + 0 + ); +}; +``` +
    Examples -```js -console.log(sdbm('name')); // -3521204949 -``` +```js +console.log(sdbm('name')); // -3521204949 +```

    [⬆ Back to top](#table-of-contents) -### standardDeviation - -Returns the standard deviation of an array of numbers. - -Use `Array.reduce()` to calculate the mean, variance and the sum of the variance of the values, the variance of the values, then -determine the standard deviation. -You can omit the second argument to get the sample standard deviation or set it to `true` to get the population standard deviation. - -```js -const standardDeviation = (arr, usePopulation = false) => { - const mean = arr.reduce((acc, val) => acc + val, 0) / arr.length; - return Math.sqrt( - arr.reduce((acc, val) => acc.concat((val - mean) ** 2), []).reduce((acc, val) => acc + val, 0) / - (arr.length - (usePopulation ? 0 : 1)) - ); -}; -``` - +### standardDeviation + +Returns the standard deviation of an array of numbers. + +Use `Array.reduce()` to calculate the mean, variance and the sum of the variance of the values, the variance of the values, then +determine the standard deviation. +You can omit the second argument to get the sample standard deviation or set it to `true` to get the population standard deviation. + +```js +const standardDeviation = (arr, usePopulation = false) => { + const mean = arr.reduce((acc, val) => acc + val, 0) / arr.length; + return Math.sqrt( + arr.reduce((acc, val) => acc.concat((val - mean) ** 2), []).reduce((acc, val) => acc + val, 0) / + (arr.length - (usePopulation ? 0 : 1)) + ); +}; +``` +
    Examples -```js -standardDeviation([10, 2, 38, 23, 38, 23, 21]); // 13.284434142114991 (sample) -standardDeviation([10, 2, 38, 23, 38, 23, 21], true); // 12.29899614287479 (population) -``` +```js +standardDeviation([10, 2, 38, 23, 38, 23, 21]); // 13.284434142114991 (sample) +standardDeviation([10, 2, 38, 23, 38, 23, 21], true); // 12.29899614287479 (population) +```

    [⬆ Back to top](#table-of-contents) -### sum - -Returns the sum of two or more numbers/arrays. - -Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`. - -```js -const sum = (...arr) => [...arr].reduce((acc, val) => acc + val, 0); -``` - +### sum + +Returns the sum of two or more numbers/arrays. + +Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`. + +```js +const sum = (...arr) => [...arr].reduce((acc, val) => acc + val, 0); +``` +
    Examples -```js -sum(...[1, 2, 3, 4]); // 10 -``` +```js +sum(...[1, 2, 3, 4]); // 10 +```

    [⬆ Back to top](#table-of-contents) -### sumPower - -Returns the sum of the powers of all the numbers from `start` to `end` (both inclusive). - -Use `Array.fill()` to create an array of all the numbers in the target range, `Array.map()` and the exponent operator (`**`) to raise them to `power` and `Array.reduce()` to add them together. -Omit the second argument, `power`, to use a default power of `2`. -Omit the third argument, `start`, to use a default starting value of `1`. - -```js -const sumPower = (end, power = 2, start = 1) => - Array(end + 1 - start) - .fill(0) - .map((x, i) => (i + start) ** power) - .reduce((a, b) => a + b, 0); -``` - +### sumPower + +Returns the sum of the powers of all the numbers from `start` to `end` (both inclusive). + +Use `Array.fill()` to create an array of all the numbers in the target range, `Array.map()` and the exponent operator (`**`) to raise them to `power` and `Array.reduce()` to add them together. +Omit the second argument, `power`, to use a default power of `2`. +Omit the third argument, `start`, to use a default starting value of `1`. + +```js +const sumPower = (end, power = 2, start = 1) => + Array(end + 1 - start) + .fill(0) + .map((x, i) => (i + start) ** power) + .reduce((a, b) => a + b, 0); +``` +
    Examples -```js -sumPower(10); // 385 -sumPower(10, 3); //3025 -sumPower(10, 3, 5); //2925 -``` +```js +sumPower(10); // 385 +sumPower(10, 3); //3025 +sumPower(10, 3, 5); //2925 +```
    @@ -3471,159 +3471,159 @@ sumPower(10, 3, 5); //2925 --- ## 📦 Node -### hasFlags - -Check if the current process's arguments contain the specified flags. - -Use `Array.every()` and `Array.includes()` to check if `process.argv` contains all the specified flags. -Use a regular expression to test if the specified flags are prefixed with `-` or `--` and prefix them accordingly. - -```js -const hasFlags = (...flags) => - flags.every(flag => process.argv.includes(/^-{1,2}/.test(flag) ? flag : '--' + flag)); -``` - +### hasFlags + +Check if the current process's arguments contain the specified flags. + +Use `Array.every()` and `Array.includes()` to check if `process.argv` contains all the specified flags. +Use a regular expression to test if the specified flags are prefixed with `-` or `--` and prefix them accordingly. + +```js +const hasFlags = (...flags) => + flags.every(flag => process.argv.includes(/^-{1,2}/.test(flag) ? flag : '--' + flag)); +``` +
    Examples -```js -// node myScript.js -s --test --cool=true -hasFlags('-s'); // true -hasFlags('--test', 'cool=true', '-s'); // true -hasFlags('special'); // false -``` +```js +// node myScript.js -s --test --cool=true +hasFlags('-s'); // true +hasFlags('--test', 'cool=true', '-s'); // true +hasFlags('special'); // false +```

    [⬆ Back to top](#table-of-contents) -### isTravisCI - -Checks if the current environment is [Travis CI](https://travis-ci.org/). - -Checks if the current environment has the `TRAVIS` and `CI` environment variables ([reference](https://docs.travis-ci.com/user/environment-variables/#Default-Environment-Variables)). - -```js -const isTravisCI = () => 'TRAVIS' in process.env && 'CI' in process.env; -``` - +### isTravisCI + +Checks if the current environment is [Travis CI](https://travis-ci.org/). + +Checks if the current environment has the `TRAVIS` and `CI` environment variables ([reference](https://docs.travis-ci.com/user/environment-variables/#Default-Environment-Variables)). + +```js +const isTravisCI = () => 'TRAVIS' in process.env && 'CI' in process.env; +``` +
    Examples -```js -isTravisCI(); // true (if code is running on Travis CI) -``` +```js +isTravisCI(); // true (if code is running on Travis CI) +```

    [⬆ Back to top](#table-of-contents) -### JSONToFile - -Writes a JSON object to a file. - -Use `fs.writeFile()`, template literals and `JSON.stringify()` to write a `json` object to a `.json` file. - -```js -const fs = require('fs'); -const JSONToFile = (obj, filename) => - fs.writeFile(`${filename}.json`, JSON.stringify(obj, null, 2)); -``` - +### JSONToFile + +Writes a JSON object to a file. + +Use `fs.writeFile()`, template literals and `JSON.stringify()` to write a `json` object to a `.json` file. + +```js +const fs = require('fs'); +const JSONToFile = (obj, filename) => + fs.writeFile(`${filename}.json`, JSON.stringify(obj, null, 2)); +``` +
    Examples -```js -JSONToFile({ test: 'is passed' }, 'testJsonFile'); // writes the object to 'testJsonFile.json' -``` +```js +JSONToFile({ test: 'is passed' }, 'testJsonFile'); // writes the object to 'testJsonFile.json' +```

    [⬆ Back to top](#table-of-contents) -### readFileLines - -Returns an array of lines from the specified file. - -Use `readFileSync` function in `fs` node package to create a `Buffer` from a file. -convert buffer to string using `toString(encoding)` function. -creating an array from contents of file by `split`ing file content line by line (each `\n`). - -```js -const fs = require('fs'); -const readFileLines = filename => - fs - .readFileSync(filename) - .toString('UTF8') - .split('\n'); -``` - +### readFileLines + +Returns an array of lines from the specified file. + +Use `readFileSync` function in `fs` node package to create a `Buffer` from a file. +convert buffer to string using `toString(encoding)` function. +creating an array from contents of file by `split`ing file content line by line (each `\n`). + +```js +const fs = require('fs'); +const readFileLines = filename => + fs + .readFileSync(filename) + .toString('UTF8') + .split('\n'); +``` +
    Examples -```js -/* -contents of test.txt : - line1 - line2 - line3 - ___________________________ -*/ -let arr = readFileLines('test.txt'); -console.log(arr); // ['line1', 'line2', 'line3'] -``` - +```js +/* +contents of test.txt : + line1 + line2 + line3 + ___________________________ +*/ +let arr = readFileLines('test.txt'); +console.log(arr); // ['line1', 'line2', 'line3'] +``` +

    [⬆ Back to top](#table-of-contents) -### untildify - -Converts a tilde path to an absolute path. - -Use `String.replace()` with a regular expression and `OS.homedir()` to replace the `~` in the start of the path with the home directory. - -```js -const untildify = str => str.replace(/^~($|\/|\\)/, `${require('os').homedir()}$1`); -``` - +### untildify + +Converts a tilde path to an absolute path. + +Use `String.replace()` with a regular expression and `OS.homedir()` to replace the `~` in the start of the path with the home directory. + +```js +const untildify = str => str.replace(/^~($|\/|\\)/, `${require('os').homedir()}$1`); +``` +
    Examples -```js -untildify('~/node'); // '/Users/aUser/node' -``` +```js +untildify('~/node'); // '/Users/aUser/node' +```

    [⬆ Back to top](#table-of-contents) -### UUIDGeneratorNode - -Generates a UUID in Node.JS. - -Use `crypto` API to generate a UUID, compliant with [RFC4122](https://www.ietf.org/rfc/rfc4122.txt) version 4. - -```js -const crypto = require('crypto'); -const UUIDGeneratorNode = () => - ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c => - (c ^ (crypto.randomBytes(1)[0] & (15 >> (c / 4)))).toString(16) - ); -``` - +### UUIDGeneratorNode + +Generates a UUID in Node.JS. + +Use `crypto` API to generate a UUID, compliant with [RFC4122](https://www.ietf.org/rfc/rfc4122.txt) version 4. + +```js +const crypto = require('crypto'); +const UUIDGeneratorNode = () => + ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c => + (c ^ (crypto.randomBytes(1)[0] & (15 >> (c / 4)))).toString(16) + ); +``` +
    Examples -```js -UUIDGeneratorNode(); // '79c7c136-60ee-40a2-beb2-856f1feabefc' -``` +```js +UUIDGeneratorNode(); // '79c7c136-60ee-40a2-beb2-856f1feabefc' +```
    @@ -3632,268 +3632,268 @@ UUIDGeneratorNode(); // '79c7c136-60ee-40a2-beb2-856f1feabefc' --- ## 🗃️ Object -### cleanObj - -Removes any properties except the ones specified from a JSON object. - -Use `Object.keys()` method to loop over given JSON object and deleting keys that are not included in given array. -If you pass a special key,`childIndicator`, it will search deeply apply the function to inner objects, too. - -```js -const cleanObj = (obj, keysToKeep = [], childIndicator) => { - Object.keys(obj).forEach(key => { - if (key === childIndicator) { - cleanObj(obj[key], keysToKeep, childIndicator); - } else if (!keysToKeep.includes(key)) { - delete obj[key]; - } - }); - return obj; -}; -``` - +### cleanObj + +Removes any properties except the ones specified from a JSON object. + +Use `Object.keys()` method to loop over given JSON object and deleting keys that are not included in given array. +If you pass a special key,`childIndicator`, it will search deeply apply the function to inner objects, too. + +```js +const cleanObj = (obj, keysToKeep = [], childIndicator) => { + Object.keys(obj).forEach(key => { + if (key === childIndicator) { + cleanObj(obj[key], keysToKeep, childIndicator); + } else if (!keysToKeep.includes(key)) { + delete obj[key]; + } + }); + return obj; +}; +``` +
    Examples -```js -const testObj = { a: 1, b: 2, children: { a: 1, b: 2 } }; -cleanObj(testObj, ['a'], 'children'); // { a: 1, children : { a: 1}} -``` +```js +const testObj = { a: 1, b: 2, children: { a: 1, b: 2 } }; +cleanObj(testObj, ['a'], 'children'); // { a: 1, children : { a: 1}} +```

    [⬆ Back to top](#table-of-contents) -### invertKeyValues - -Inverts the key-value pairs of an object, without mutating it. - -Use `Object.keys()` and `Array.reduce()` to invert the key-value pairs of an object. - -```js -const invertKeyValues = obj => - Object.keys(obj).reduce((acc, key) => { - acc[obj[key]] = key; - return acc; - }, {}); -``` - +### invertKeyValues + +Inverts the key-value pairs of an object, without mutating it. + +Use `Object.keys()` and `Array.reduce()` to invert the key-value pairs of an object. + +```js +const invertKeyValues = obj => + Object.keys(obj).reduce((acc, key) => { + acc[obj[key]] = key; + return acc; + }, {}); +``` +
    Examples -```js -invertKeyValues({ name: 'John', age: 20 }); // { 20: 'age', John: 'name' } -``` +```js +invertKeyValues({ name: 'John', age: 20 }); // { 20: 'age', John: 'name' } +```

    [⬆ Back to top](#table-of-contents) -### lowercaseKeys - -Creates a new object from the specified object, where all the keys are in lowercase. - -Use `Object.keys()` and `Array.reduce()` to create a new object from the specified object. -Convert each key in the original object to lowercase, using `String.toLowerCase()`. - -```js -const lowercaseKeys = obj => - Object.keys(obj).reduce((acc, key) => { - acc[key.toLowerCase()] = obj[key]; - return acc; - }, {}); -``` - +### lowercaseKeys + +Creates a new object from the specified object, where all the keys are in lowercase. + +Use `Object.keys()` and `Array.reduce()` to create a new object from the specified object. +Convert each key in the original object to lowercase, using `String.toLowerCase()`. + +```js +const lowercaseKeys = obj => + Object.keys(obj).reduce((acc, key) => { + acc[key.toLowerCase()] = obj[key]; + return acc; + }, {}); +``` +
    Examples -```js -const myObj = { Name: 'Adam', sUrnAME: 'Smith' }; -const myObjLower = lowercaseKeys(myObj); // {name: 'Adam', surname: 'Smith'}; -``` +```js +const myObj = { Name: 'Adam', sUrnAME: 'Smith' }; +const myObjLower = lowercaseKeys(myObj); // {name: 'Adam', surname: 'Smith'}; +```

    [⬆ Back to top](#table-of-contents) -### objectFromPairs - -Creates an object from the given key-value pairs. - -Use `Array.reduce()` to create and combine key-value pairs. - -```js -const objectFromPairs = arr => arr.reduce((a, v) => ((a[v[0]] = v[1]), a), {}); -``` - +### objectFromPairs + +Creates an object from the given key-value pairs. + +Use `Array.reduce()` to create and combine key-value pairs. + +```js +const objectFromPairs = arr => arr.reduce((a, v) => ((a[v[0]] = v[1]), a), {}); +``` +
    Examples -```js -objectFromPairs([['a', 1], ['b', 2]]); // {a: 1, b: 2} -``` +```js +objectFromPairs([['a', 1], ['b', 2]]); // {a: 1, b: 2} +```

    [⬆ Back to top](#table-of-contents) -### objectToPairs - -Creates an array of key-value pair arrays from an object. - -Use `Object.keys()` and `Array.map()` to iterate over the object's keys and produce an array with key-value pairs. - -```js -const objectToPairs = obj => Object.keys(obj).map(k => [k, obj[k]]); -``` - +### objectToPairs + +Creates an array of key-value pair arrays from an object. + +Use `Object.keys()` and `Array.map()` to iterate over the object's keys and produce an array with key-value pairs. + +```js +const objectToPairs = obj => Object.keys(obj).map(k => [k, obj[k]]); +``` +
    Examples -```js -objectToPairs({ a: 1, b: 2 }); // [['a',1],['b',2]]) -``` +```js +objectToPairs({ a: 1, b: 2 }); // [['a',1],['b',2]]) +```

    [⬆ Back to top](#table-of-contents) -### orderBy - -Returns a sorted array of objects ordered by properties and orders. - -Uses `Array.sort()`, `Array.reduce()` on the `props` array with a default value of `0`, use array destructuring to swap the properties position depending on the order passed. -If no `orders` array is passed it sort by `'asc'` by default. - -```js -const orderBy = (arr, props, orders) => - [...arr].sort((a, b) => - props.reduce((acc, prop, i) => { - if (acc === 0) { - const [p1, p2] = orders && orders[i] === 'desc' ? [b[prop], a[prop]] : [a[prop], b[prop]]; - acc = p1 > p2 ? 1 : p1 < p2 ? -1 : 0; - } - return acc; - }, 0) - ); -``` - +### orderBy + +Returns a sorted array of objects ordered by properties and orders. + +Uses `Array.sort()`, `Array.reduce()` on the `props` array with a default value of `0`, use array destructuring to swap the properties position depending on the order passed. +If no `orders` array is passed it sort by `'asc'` by default. + +```js +const orderBy = (arr, props, orders) => + [...arr].sort((a, b) => + props.reduce((acc, prop, i) => { + if (acc === 0) { + const [p1, p2] = orders && orders[i] === 'desc' ? [b[prop], a[prop]] : [a[prop], b[prop]]; + acc = p1 > p2 ? 1 : p1 < p2 ? -1 : 0; + } + return acc; + }, 0) + ); +``` +
    Examples -```js -const users = [{ name: 'fred', age: 48 }, { name: 'barney', age: 36 }, { name: 'fred', age: 40 }]; -orderBy(users, ['name', 'age'], ['asc', 'desc']); // [{name: 'barney', age: 36}, {name: 'fred', age: 48}, {name: 'fred', age: 40}] -orderBy(users, ['name', 'age']); // [{name: 'barney', age: 36}, {name: 'fred', age: 40}, {name: 'fred', age: 48}] -``` +```js +const users = [{ name: 'fred', age: 48 }, { name: 'barney', age: 36 }, { name: 'fred', age: 40 }]; +orderBy(users, ['name', 'age'], ['asc', 'desc']); // [{name: 'barney', age: 36}, {name: 'fred', age: 48}, {name: 'fred', age: 40}] +orderBy(users, ['name', 'age']); // [{name: 'barney', age: 36}, {name: 'fred', age: 40}, {name: 'fred', age: 48}] +```

    [⬆ Back to top](#table-of-contents) -### select - -Retrieve a property indicated by the selector from an object. - -If the property does not exists returns `undefined`. - -```js -const select = (from, selector) => - selector.split('.').reduce((prev, cur) => prev && prev[cur], from); -``` - +### select + +Retrieve a property indicated by the selector from an object. + +If the property does not exists returns `undefined`. + +```js +const select = (from, selector) => + selector.split('.').reduce((prev, cur) => prev && prev[cur], from); +``` +
    Examples -```js -const obj = { selector: { to: { val: 'val to select' } } }; -select(obj, 'selector.to.val'); // 'val to select' -``` +```js +const obj = { selector: { to: { val: 'val to select' } } }; +select(obj, 'selector.to.val'); // 'val to select' +```

    [⬆ Back to top](#table-of-contents) -### shallowClone - -Creates a shallow clone of an object. - -Use `Object.assign()` and an empty object (`{}`) to create a shallow clone of the original. - -```js -const shallowClone = obj => Object.assign({}, obj); -``` - +### shallowClone + +Creates a shallow clone of an object. + +Use `Object.assign()` and an empty object (`{}`) to create a shallow clone of the original. + +```js +const shallowClone = obj => Object.assign({}, obj); +``` +
    Examples -```js -const a = { x: true, y: 1 }; -const b = shallowClone(a); // a !== b -``` +```js +const a = { x: true, y: 1 }; +const b = shallowClone(a); // a !== b +```

    [⬆ Back to top](#table-of-contents) -### size - -Get size of arrays, objects or strings. - -Get type of `val` (`array`, `object` or `string`). -Use `length` property for arrays. -Use `length` or `size` value if available or number of keys for objects. -Use `size` of a [`Blob` object](https://developer.mozilla.org/en-US/docs/Web/API/Blob) created from `val` for strings. - -Split strings into array of characters with `split('')` and return its length. - -```js -const size = val => - Array.isArray(val) - ? val.length - : val && typeof val === 'object' - ? val.size || val.length || Object.keys(val).length - : typeof val === 'string' ? new Blob([val]).size : 0; -``` - +### size + +Get size of arrays, objects or strings. + +Get type of `val` (`array`, `object` or `string`). +Use `length` property for arrays. +Use `length` or `size` value if available or number of keys for objects. +Use `size` of a [`Blob` object](https://developer.mozilla.org/en-US/docs/Web/API/Blob) created from `val` for strings. + +Split strings into array of characters with `split('')` and return its length. + +```js +const size = val => + Array.isArray(val) + ? val.length + : val && typeof val === 'object' + ? val.size || val.length || Object.keys(val).length + : typeof val === 'string' ? new Blob([val]).size : 0; +``` +
    Examples -```js -size([1, 2, 3, 4, 5]); // 5 -size('size'); // 4 -size({ one: 1, two: 2, three: 3 }); // 3 -``` +```js +size([1, 2, 3, 4, 5]); // 5 +size('size'); // 4 +size({ one: 1, two: 2, three: 3 }); // 3 +```

    [⬆ Back to top](#table-of-contents) -### truthCheckCollection - -Checks if the predicate (second argument) is truthy on all elements of a collection (first argument). - -Use `Array.every()` to check if each passed object has the specified property and if it returns a truthy value. - -```js -const truthCheckCollection = (collection, pre) => collection.every(obj => obj[pre]); -``` - +### truthCheckCollection + +Checks if the predicate (second argument) is truthy on all elements of a collection (first argument). + +Use `Array.every()` to check if each passed object has the specified property and if it returns a truthy value. + +```js +const truthCheckCollection = (collection, pre) => collection.every(obj => obj[pre]); +``` +
    Examples -```js -truthCheckCollection([{ user: 'Tinky-Winky', sex: 'male' }, { user: 'Dipsy', sex: 'male' }], 'sex'); // true -``` +```js +truthCheckCollection([{ user: 'Tinky-Winky', sex: 'male' }, { user: 'Dipsy', sex: 'male' }], 'sex'); // true +```
    @@ -3902,626 +3902,626 @@ truthCheckCollection([{ user: 'Tinky-Winky', sex: 'male' }, { user: 'Dipsy', sex --- ## 📜 String -### anagrams - -⚠️ **WARNING**: This function's execution time increases exponentially with each character. Anything more than 8 to 10 characters will cause your browser to hang as it tries to solve all the different combinations. - -Generates all anagrams of a string (contains duplicates). - -Use recursion. -For each letter in the given string, create all the partial anagrams for the rest of its letters. -Use `Array.map()` to combine the letter with each partial anagram, then `Array.reduce()` to combine all anagrams in one array. -Base cases are for string `length` equal to `2` or `1`. - -```js -const anagrams = str => { - if (str.length <= 2) return str.length === 2 ? [str, str[1] + str[0]] : [str]; - return str - .split('') - .reduce( - (acc, letter, i) => - acc.concat(anagrams(str.slice(0, i) + str.slice(i + 1)).map(val => letter + val)), - [] - ); -}; -``` - +### anagrams + +⚠️ **WARNING**: This function's execution time increases exponentially with each character. Anything more than 8 to 10 characters will cause your browser to hang as it tries to solve all the different combinations. + +Generates all anagrams of a string (contains duplicates). + +Use recursion. +For each letter in the given string, create all the partial anagrams for the rest of its letters. +Use `Array.map()` to combine the letter with each partial anagram, then `Array.reduce()` to combine all anagrams in one array. +Base cases are for string `length` equal to `2` or `1`. + +```js +const anagrams = str => { + if (str.length <= 2) return str.length === 2 ? [str, str[1] + str[0]] : [str]; + return str + .split('') + .reduce( + (acc, letter, i) => + acc.concat(anagrams(str.slice(0, i) + str.slice(i + 1)).map(val => letter + val)), + [] + ); +}; +``` +
    Examples -```js -anagrams('abc'); // ['abc','acb','bac','bca','cab','cba'] -``` +```js +anagrams('abc'); // ['abc','acb','bac','bca','cab','cba'] +```

    [⬆ Back to top](#table-of-contents) -### byteSize - -Returns the length of a string in bytes. - -Convert a given string to a [`Blob` Object](https://developer.mozilla.org/en-US/docs/Web/API/Blob) and find its `size`. - -```js -const byteSize = str => new Blob([str]).size; -``` - +### byteSize + +Returns the length of a string in bytes. + +Convert a given string to a [`Blob` Object](https://developer.mozilla.org/en-US/docs/Web/API/Blob) and find its `size`. + +```js +const byteSize = str => new Blob([str]).size; +``` +
    Examples -```js -byteSize('😀'); // 4 -byteSize('Hello World'); // 11 -``` +```js +byteSize('😀'); // 4 +byteSize('Hello World'); // 11 +```

    [⬆ Back to top](#table-of-contents) -### capitalize - -Capitalizes the first letter of a string. - -Use array destructuring and `String.toUpperCase()` to capitalize first letter, `...rest` to get array of characters after first letter and then `Array.join('')` to make it a string again. -Omit the `lowerRest` parameter to keep the rest of the string intact, or set it to `true` to convert to lowercase. - -```js -const capitalize = ([first, ...rest], lowerRest = false) => - first.toUpperCase() + (lowerRest ? rest.join('').toLowerCase() : rest.join('')); -``` - +### capitalize + +Capitalizes the first letter of a string. + +Use array destructuring and `String.toUpperCase()` to capitalize first letter, `...rest` to get array of characters after first letter and then `Array.join('')` to make it a string again. +Omit the `lowerRest` parameter to keep the rest of the string intact, or set it to `true` to convert to lowercase. + +```js +const capitalize = ([first, ...rest], lowerRest = false) => + first.toUpperCase() + (lowerRest ? rest.join('').toLowerCase() : rest.join('')); +``` +
    Examples -```js -capitalize('fooBar'); // 'FooBar' -capitalize('fooBar', true); // 'Foobar' -``` +```js +capitalize('fooBar'); // 'FooBar' +capitalize('fooBar', true); // 'Foobar' +```

    [⬆ Back to top](#table-of-contents) -### capitalizeEveryWord - -Capitalizes the first letter of every word in a string. - -Use `String.replace()` to match the first character of each word and `String.toUpperCase()` to capitalize it. - -```js -const capitalizeEveryWord = str => str.replace(/\b[a-z]/g, char => char.toUpperCase()); -``` - +### capitalizeEveryWord + +Capitalizes the first letter of every word in a string. + +Use `String.replace()` to match the first character of each word and `String.toUpperCase()` to capitalize it. + +```js +const capitalizeEveryWord = str => str.replace(/\b[a-z]/g, char => char.toUpperCase()); +``` +
    Examples -```js -capitalizeEveryWord('hello world!'); // 'Hello World!' -``` +```js +capitalizeEveryWord('hello world!'); // 'Hello World!' +```

    [⬆ Back to top](#table-of-contents) -### countVowels - -Retuns `number` of vowels in provided string. - -Use a regular expression to count the number of vowels `(A, E, I, O, U)` in a `string`. - -```js -const countVowels = str => (str.match(/[aeiou]/gi) || []).length; -``` - +### countVowels + +Retuns `number` of vowels in provided string. + +Use a regular expression to count the number of vowels `(A, E, I, O, U)` in a `string`. + +```js +const countVowels = str => (str.match(/[aeiou]/gi) || []).length; +``` +
    Examples -```js -countVowels('foobar'); // 3 -countVowels('gym'); // 0 -``` +```js +countVowels('foobar'); // 3 +countVowels('gym'); // 0 +```

    [⬆ Back to top](#table-of-contents) -### escapeHTML - -Escapes a string for use in HTML. - -Use `String.replace()` with a regexp that matches the characters that need to be escaped, using a callback function to replace each character instance with its associated escaped character using a dictionary (object). - -```js -const escapeHTML = str => - str.replace( - /[&<>'"]/g, - tag => - ({ - '&': '&', - '<': '<', - '>': '>', - "'": ''', - '"': '"' - }[tag] || tag) - ); -``` - +### escapeHTML + +Escapes a string for use in HTML. + +Use `String.replace()` with a regexp that matches the characters that need to be escaped, using a callback function to replace each character instance with its associated escaped character using a dictionary (object). + +```js +const escapeHTML = str => + str.replace( + /[&<>'"]/g, + tag => + ({ + '&': '&', + '<': '<', + '>': '>', + "'": ''', + '"': '"' + }[tag] || tag) + ); +``` +
    Examples -```js -escapeHTML('Me & you'); // '<a href="#">Me & you</a>' -``` +```js +escapeHTML('Me & you'); // '<a href="#">Me & you</a>' +```

    [⬆ Back to top](#table-of-contents) -### escapeRegExp - -Escapes a string to use in a regular expression. - -Use `String.replace()` to escape special characters. - -```js -const escapeRegExp = str => str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); -``` - +### escapeRegExp + +Escapes a string to use in a regular expression. + +Use `String.replace()` to escape special characters. + +```js +const escapeRegExp = str => str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); +``` +
    Examples -```js -escapeRegExp('(test)'); // \\(test\\) -``` +```js +escapeRegExp('(test)'); // \\(test\\) +```

    [⬆ Back to top](#table-of-contents) -### fromCamelCase - -Converts a string from camelcase. - -Use `String.replace()` to remove underscores, hyphens, and spaces and convert words to camelcase. -Omit the second argument to use a default `separator` of `_`. - -```js -const fromCamelCase = (str, separator = '_') => - str - .replace(/([a-z\d])([A-Z])/g, '$1' + separator + '$2') - .replace(/([A-Z]+)([A-Z][a-z\d]+)/g, '$1' + separator + '$2') - .toLowerCase(); -``` - +### fromCamelCase + +Converts a string from camelcase. + +Use `String.replace()` to remove underscores, hyphens, and spaces and convert words to camelcase. +Omit the second argument to use a default `separator` of `_`. + +```js +const fromCamelCase = (str, separator = '_') => + str + .replace(/([a-z\d])([A-Z])/g, '$1' + separator + '$2') + .replace(/([A-Z]+)([A-Z][a-z\d]+)/g, '$1' + separator + '$2') + .toLowerCase(); +``` +
    Examples -```js -fromCamelCase('someDatabaseFieldName', ' '); // 'some database field name' -fromCamelCase('someLabelThatNeedsToBeCamelized', '-'); // 'some-label-that-needs-to-be-camelized' -fromCamelCase('someJavascriptProperty', '_'); // 'some_javascript_property' -``` +```js +fromCamelCase('someDatabaseFieldName', ' '); // 'some database field name' +fromCamelCase('someLabelThatNeedsToBeCamelized', '-'); // 'some-label-that-needs-to-be-camelized' +fromCamelCase('someJavascriptProperty', '_'); // 'some_javascript_property' +```

    [⬆ Back to top](#table-of-contents) -### isAbsoluteURL - -Returns `true` if the given string is an absolute URL, `false` otherwise. - -Use a regular expression to test if the string is an absolute URL. - -```js -const isAbsoluteURL = str => /^[a-z][a-z0-9+.-]*:/.test(str); -``` - +### isAbsoluteURL + +Returns `true` if the given string is an absolute URL, `false` otherwise. + +Use a regular expression to test if the string is an absolute URL. + +```js +const isAbsoluteURL = str => /^[a-z][a-z0-9+.-]*:/.test(str); +``` +
    Examples -```js -isAbsoluteURL('https://google.com'); // true -isAbsoluteURL('ftp://www.myserver.net'); // true -isAbsoluteURL('/foo/bar'); // false -``` +```js +isAbsoluteURL('https://google.com'); // true +isAbsoluteURL('ftp://www.myserver.net'); // true +isAbsoluteURL('/foo/bar'); // false +```

    [⬆ Back to top](#table-of-contents) -### isLowerCase - -Checks if a string is lower case. - -Convert the given string to lower case, using `String.toLowerCase()` and compare it to the original. - -```js -const isLowerCase = str => str === str.toLowerCase(); -``` - +### isLowerCase + +Checks if a string is lower case. + +Convert the given string to lower case, using `String.toLowerCase()` and compare it to the original. + +```js +const isLowerCase = str => str === str.toLowerCase(); +``` +
    Examples -```js -isLowerCase('abc'); // true -isLowerCase('a3@$'); // true -isLowerCase('Ab4'); // false -``` +```js +isLowerCase('abc'); // true +isLowerCase('a3@$'); // true +isLowerCase('Ab4'); // false +```

    [⬆ Back to top](#table-of-contents) -### isUpperCase - -Checks if a string is upper case. - -Convert the given string to upper case, using `String.toUpperCase()` and compare it to the original. - - -```js -const isUpperCase = str => str === str.toUpperCase(); -``` - +### isUpperCase + +Checks if a string is upper case. + +Convert the given string to upper case, using `String.toUpperCase()` and compare it to the original. + + +```js +const isUpperCase = str => str === str.toUpperCase(); +``` +
    Examples -```js -isUpperCase('ABC'); // true -isLowerCase('A3@$'); // true -isLowerCase('aB4'); // false -``` +```js +isUpperCase('ABC'); // true +isLowerCase('A3@$'); // true +isLowerCase('aB4'); // false +```

    [⬆ Back to top](#table-of-contents) -### mask - -Replaces all but the last `num` of characters with the specified mask character. - -Use `String.slice()` to grab the portion of the characters that need to be masked and use `String.replace()` with a regexp to replace every character with the mask character. -Concatenate the masked characters with the remaining unmasked portion of the string. -Omit the second argument, `num`, to keep a default of `4` characters unmasked. If `num` is negative, the unmasked characters will be at the start of the string. -Omit the third argument, `mask`, to use a default character of `'*'` for the mask. - -```js -const mask = (cc, num = 4, mask = '*') => - ('' + cc).slice(0, -num).replace(/./g, mask) + ('' + cc).slice(-num); -``` - +### mask + +Replaces all but the last `num` of characters with the specified mask character. + +Use `String.slice()` to grab the portion of the characters that need to be masked and use `String.replace()` with a regexp to replace every character with the mask character. +Concatenate the masked characters with the remaining unmasked portion of the string. +Omit the second argument, `num`, to keep a default of `4` characters unmasked. If `num` is negative, the unmasked characters will be at the start of the string. +Omit the third argument, `mask`, to use a default character of `'*'` for the mask. + +```js +const mask = (cc, num = 4, mask = '*') => + ('' + cc).slice(0, -num).replace(/./g, mask) + ('' + cc).slice(-num); +``` +
    Examples -```js -mask(1234567890); // '******7890' -mask(1234567890, 3); // '*******890' -mask(1234567890, -4, '$'); // '1234$$$$$$' -``` +```js +mask(1234567890); // '******7890' +mask(1234567890, 3); // '*******890' +mask(1234567890, -4, '$'); // '1234$$$$$$' +```

    [⬆ Back to top](#table-of-contents) -### palindrome - -Returns `true` if the given string is a palindrome, `false` otherwise. - -Convert string `String.toLowerCase()` and use `String.replace()` to remove non-alphanumeric characters from it. -Then, `String.split('')` into individual characters, `Array.reverse()`, `String.join('')` and compare to the original, unreversed string, after converting it `String.tolowerCase()`. - -```js -const palindrome = str => { - const s = str.toLowerCase().replace(/[\W_]/g, ''); - return ( - s === - s - .split('') - .reverse() - .join('') - ); -}; -``` - +### palindrome + +Returns `true` if the given string is a palindrome, `false` otherwise. + +Convert string `String.toLowerCase()` and use `String.replace()` to remove non-alphanumeric characters from it. +Then, `String.split('')` into individual characters, `Array.reverse()`, `String.join('')` and compare to the original, unreversed string, after converting it `String.tolowerCase()`. + +```js +const palindrome = str => { + const s = str.toLowerCase().replace(/[\W_]/g, ''); + return ( + s === + s + .split('') + .reverse() + .join('') + ); +}; +``` +
    Examples -```js -palindrome('taco cat'); // true -``` +```js +palindrome('taco cat'); // true +```

    [⬆ Back to top](#table-of-contents) -### pluralize - -Returns the singular or plural form of the word based on the input number. If the first argument is an `object`, it will use a closure by returning a function that can auto-pluralize words that don't simply end in `s` if the supplied dictionary contains the word. - -If `num` is either `-1` or `1`, return the singular form of the word. If `num` is any other number, return the plural form. Omit the third argument to use the default of the singular word + `s`, or supply a custom pluralized word when necessary. If the first argument is an `object`, utilize a closure by returning a function which can use the supplied dictionary to resolve the correct plural form of the word. - -```js -const pluralize = (val, word, plural = word + 's') => { - const _pluralize = (num, word, plural = word + 's') => - [1, -1].includes(Number(num)) ? word : plural; - if (typeof val === 'object') return (num, word) => _pluralize(num, word, val[word]); - return _pluralize(val, word, plural); -}; -``` - +### pluralize + +Returns the singular or plural form of the word based on the input number. If the first argument is an `object`, it will use a closure by returning a function that can auto-pluralize words that don't simply end in `s` if the supplied dictionary contains the word. + +If `num` is either `-1` or `1`, return the singular form of the word. If `num` is any other number, return the plural form. Omit the third argument to use the default of the singular word + `s`, or supply a custom pluralized word when necessary. If the first argument is an `object`, utilize a closure by returning a function which can use the supplied dictionary to resolve the correct plural form of the word. + +```js +const pluralize = (val, word, plural = word + 's') => { + const _pluralize = (num, word, plural = word + 's') => + [1, -1].includes(Number(num)) ? word : plural; + if (typeof val === 'object') return (num, word) => _pluralize(num, word, val[word]); + return _pluralize(val, word, plural); +}; +``` +
    Examples -```js -pluralize(0, 'apple'); // 'apples' -pluralize(1, 'apple'); // 'apple' -pluralize(2, 'apple'); // 'apples' -pluralize(2, 'person', 'people'); // 'people' - -const PLURALS = { - person: 'people', - radius: 'radii' -}; -const autoPluralize = pluralize(PLURALS); -autoPluralize(2, 'person'); // 'people' -``` +```js +pluralize(0, 'apple'); // 'apples' +pluralize(1, 'apple'); // 'apple' +pluralize(2, 'apple'); // 'apples' +pluralize(2, 'person', 'people'); // 'people' + +const PLURALS = { + person: 'people', + radius: 'radii' +}; +const autoPluralize = pluralize(PLURALS); +autoPluralize(2, 'person'); // 'people' +```

    [⬆ Back to top](#table-of-contents) -### reverseString - -Reverses a string. - -Use the spread operator (`...`) and `Array.reverse()` to reverse the order of the characters in the string. -Combine characters to get a string using `String.join('')`. - -```js -const reverseString = str => [...str].reverse().join(''); -``` - +### reverseString + +Reverses a string. + +Use the spread operator (`...`) and `Array.reverse()` to reverse the order of the characters in the string. +Combine characters to get a string using `String.join('')`. + +```js +const reverseString = str => [...str].reverse().join(''); +``` +
    Examples -```js -reverseString('foobar'); // 'raboof' -``` +```js +reverseString('foobar'); // 'raboof' +```

    [⬆ Back to top](#table-of-contents) -### sortCharactersInString - -Alphabetically sorts the characters in a string. - -Use the spread operator (`...`), `Array.sort()` and `String.localeCompare()` to sort the characters in `str`, recombine using `String.join('')`. - -```js -const sortCharactersInString = str => [...str].sort((a, b) => a.localeCompare(b)).join(''); -``` - +### sortCharactersInString + +Alphabetically sorts the characters in a string. + +Use the spread operator (`...`), `Array.sort()` and `String.localeCompare()` to sort the characters in `str`, recombine using `String.join('')`. + +```js +const sortCharactersInString = str => [...str].sort((a, b) => a.localeCompare(b)).join(''); +``` +
    Examples -```js -sortCharactersInString('cabbage'); // 'aabbceg' -``` +```js +sortCharactersInString('cabbage'); // 'aabbceg' +```

    [⬆ Back to top](#table-of-contents) -### splitLines - -Splits a multiline string into an array of lines. - -Use `String.split()` and a regular expression to match line breaks and create an array. - -```js -const splitLines = str => str.split(/\r?\n/); -``` - +### splitLines + +Splits a multiline string into an array of lines. + +Use `String.split()` and a regular expression to match line breaks and create an array. + +```js +const splitLines = str => str.split(/\r?\n/); +``` +
    Examples -```js -splitLines('This\nis a\nmultiline\nstring.\n'); // ['This', 'is a', 'multiline', 'string' , ''] -``` +```js +splitLines('This\nis a\nmultiline\nstring.\n'); // ['This', 'is a', 'multiline', 'string' , ''] +```

    [⬆ Back to top](#table-of-contents) -### toCamelCase - -Converts a string to camelcase. - -Break the string into words and combine them capitalizing the first letter of each word, using a regexp. - -```js -const toCamelCase = str => { - let s = - str && - str - .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) - .map(x => x.slice(0, 1).toUpperCase() + x.slice(1).toLowerCase()) - .join(''); - return s.slice(0, 1).toLowerCase() + s.slice(1); -}; -``` - +### toCamelCase + +Converts a string to camelcase. + +Break the string into words and combine them capitalizing the first letter of each word, using a regexp. + +```js +const toCamelCase = str => { + let s = + str && + str + .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) + .map(x => x.slice(0, 1).toUpperCase() + x.slice(1).toLowerCase()) + .join(''); + return s.slice(0, 1).toLowerCase() + s.slice(1); +}; +``` +
    Examples -```js -toCamelCase('some_database_field_name'); // 'someDatabaseFieldName' -toCamelCase('Some label that needs to be camelized'); // 'someLabelThatNeedsToBeCamelized' -toCamelCase('some-javascript-property'); // 'someJavascriptProperty' -toCamelCase('some-mixed_string with spaces_underscores-and-hyphens'); // 'someMixedStringWithSpacesUnderscoresAndHyphens' -``` +```js +toCamelCase('some_database_field_name'); // 'someDatabaseFieldName' +toCamelCase('Some label that needs to be camelized'); // 'someLabelThatNeedsToBeCamelized' +toCamelCase('some-javascript-property'); // 'someJavascriptProperty' +toCamelCase('some-mixed_string with spaces_underscores-and-hyphens'); // 'someMixedStringWithSpacesUnderscoresAndHyphens' +```

    [⬆ Back to top](#table-of-contents) -### toKebabCase - -Converts a string to kebab case. - -Break the string into words and combine them adding `-` as a separator, using a regexp. - -```js -const toKebabCase = str => - str && - str - .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) - .map(x => x.toLowerCase()) - .join('-'); -``` - +### toKebabCase + +Converts a string to kebab case. + +Break the string into words and combine them adding `-` as a separator, using a regexp. + +```js +const toKebabCase = str => + str && + str + .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) + .map(x => x.toLowerCase()) + .join('-'); +``` +
    Examples -```js -toKebabCase('camelCase'); // 'camel-case' -toKebabCase('some text'); // 'some-text' -toKebabCase('some-mixed_string With spaces_underscores-and-hyphens'); // 'some-mixed-string-with-spaces-underscores-and-hyphens' -toKebabCase('AllThe-small Things'); // "all-the-small-things" -toKebabCase('IAmListeningToFMWhileLoadingDifferentURLOnMyBrowserAndAlsoEditingSomeXMLAndHTML'); // "i-am-listening-to-fm-while-loading-different-url-on-my-browser-and-also-editing-xml-and-html" -``` +```js +toKebabCase('camelCase'); // 'camel-case' +toKebabCase('some text'); // 'some-text' +toKebabCase('some-mixed_string With spaces_underscores-and-hyphens'); // 'some-mixed-string-with-spaces-underscores-and-hyphens' +toKebabCase('AllThe-small Things'); // "all-the-small-things" +toKebabCase('IAmListeningToFMWhileLoadingDifferentURLOnMyBrowserAndAlsoEditingSomeXMLAndHTML'); // "i-am-listening-to-fm-while-loading-different-url-on-my-browser-and-also-editing-xml-and-html" +```

    [⬆ Back to top](#table-of-contents) -### toSnakeCase - -Converts a string to snake case. - -Break the string into words and combine them adding `_` as a separator, using a regexp. - -```js -const toSnakeCase = str => - str && - str - .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) - .map(x => x.toLowerCase()) - .join('_'); -``` - +### toSnakeCase + +Converts a string to snake case. + +Break the string into words and combine them adding `_` as a separator, using a regexp. + +```js +const toSnakeCase = str => + str && + str + .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) + .map(x => x.toLowerCase()) + .join('_'); +``` +
    Examples -```js -toSnakeCase('camelCase'); // 'camel_case' -toSnakeCase('some text'); // 'some_text' -toSnakeCase('some-mixed_string With spaces_underscores-and-hyphens'); // 'some_mixed_string_with_spaces_underscores_and_hyphens' -toSnakeCase('AllThe-small Things'); // "all_the_smal_things" -toSnakeCase('IAmListeningToFMWhileLoadingDifferentURLOnMyBrowserAndAlsoEditingSomeXMLAndHTML'); // "i_am_listening_to_fm_while_loading_different_url_on_my_browser_and_also_editing_some_xml_and_html" -``` +```js +toSnakeCase('camelCase'); // 'camel_case' +toSnakeCase('some text'); // 'some_text' +toSnakeCase('some-mixed_string With spaces_underscores-and-hyphens'); // 'some_mixed_string_with_spaces_underscores_and_hyphens' +toSnakeCase('AllThe-small Things'); // "all_the_smal_things" +toSnakeCase('IAmListeningToFMWhileLoadingDifferentURLOnMyBrowserAndAlsoEditingSomeXMLAndHTML'); // "i_am_listening_to_fm_while_loading_different_url_on_my_browser_and_also_editing_some_xml_and_html" +```

    [⬆ Back to top](#table-of-contents) -### truncateString - -Truncates a string up to a specified length. - -Determine if the string's `length` is greater than `num`. -Return the string truncated to the desired length, with `'...'` appended to the end or the original string. - -```js -const truncateString = (str, num) => - str.length > num ? str.slice(0, num > 3 ? num - 3 : num) + '...' : str; -``` - +### truncateString + +Truncates a string up to a specified length. + +Determine if the string's `length` is greater than `num`. +Return the string truncated to the desired length, with `'...'` appended to the end or the original string. + +```js +const truncateString = (str, num) => + str.length > num ? str.slice(0, num > 3 ? num - 3 : num) + '...' : str; +``` +
    Examples -```js -truncateString('boomerang', 7); // 'boom...' -``` +```js +truncateString('boomerang', 7); // 'boom...' +```

    [⬆ Back to top](#table-of-contents) -### unescapeHTML - -Unescapes escaped HTML characters. - -Use `String.replace()` with a regex that matches the characters that need to be unescaped, using a callback function to replace each escaped character instance with its associated unescaped character using a dictionary (object). - -```js -const unescapeHTML = str => - str.replace( - /&|<|>|'|"/g, - tag => - ({ - '&': '&', - '<': '<', - '>': '>', - ''': "'", - '"': '"' - }[tag] || tag) - ); -``` - +### unescapeHTML + +Unescapes escaped HTML characters. + +Use `String.replace()` with a regex that matches the characters that need to be unescaped, using a callback function to replace each escaped character instance with its associated unescaped character using a dictionary (object). + +```js +const unescapeHTML = str => + str.replace( + /&|<|>|'|"/g, + tag => + ({ + '&': '&', + '<': '<', + '>': '>', + ''': "'", + '"': '"' + }[tag] || tag) + ); +``` +
    Examples -```js -unescapeHTML('<a href="#">Me & you</a>'); // 'Me & you' -``` +```js +unescapeHTML('<a href="#">Me & you</a>'); // 'Me & you' +```

    [⬆ Back to top](#table-of-contents) -### words - -Converts a given string into an array of words. - -Use `String.split()` with a supplied pattern (defaults to non-alpha as a regexp) to convert to an array of strings. Use `Array.filter()` to remove any empty strings. -Omit the second argument to use the default regexp. - -```js -const words = (str, pattern = /[^a-zA-Z-]+/) => str.split(pattern).filter(Boolean); -``` - +### words + +Converts a given string into an array of words. + +Use `String.split()` with a supplied pattern (defaults to non-alpha as a regexp) to convert to an array of strings. Use `Array.filter()` to remove any empty strings. +Omit the second argument to use the default regexp. + +```js +const words = (str, pattern = /[^a-zA-Z-]+/) => str.split(pattern).filter(Boolean); +``` +
    Examples -```js -words('I love javaScript!!'); // ["I", "love", "javaScript"] -words('python, javaScript & coffee'); // ["python", "javaScript", "coffee"] -``` +```js +words('I love javaScript!!'); // ["I", "love", "javaScript"] +words('python, javaScript & coffee'); // ["python", "javaScript", "coffee"] +```
    @@ -4530,301 +4530,301 @@ words('python, javaScript & coffee'); // ["python", "javaScript", "coffee"] --- ## Type -### getType - -Returns the native type of a value. - -Returns lowercased constructor name of value, `"undefined"` or `"null"` if value is `undefined` or `null`. - -```js -const getType = v => - v === undefined ? 'undefined' : v === null ? 'null' : v.constructor.name.toLowerCase(); -``` - +### getType + +Returns the native type of a value. + +Returns lowercased constructor name of value, `"undefined"` or `"null"` if value is `undefined` or `null`. + +```js +const getType = v => + v === undefined ? 'undefined' : v === null ? 'null' : v.constructor.name.toLowerCase(); +``` +
    Examples -```js -getType(new Set([1, 2, 3])); // 'Set' -``` +```js +getType(new Set([1, 2, 3])); // 'Set' +```

    [⬆ Back to top](#table-of-contents) -### isArray - -Checks if the given argument is an array. - -Use `Array.isArray()` to check if a value is classified as an array. - -```js -const isArray = val => Array.isArray(val); -``` - +### isArray + +Checks if the given argument is an array. + +Use `Array.isArray()` to check if a value is classified as an array. + +```js +const isArray = val => Array.isArray(val); +``` +
    Examples -```js -isArray([1]); // true -``` +```js +isArray([1]); // true +```

    [⬆ Back to top](#table-of-contents) -### isArrayLike - -Checks if the provided argument is array-like (i.e. is iterable). - -Use the spread operator (`...`) to check if the provided argument is iterable inside a `try... catch` block and the comma operator (`,`) to return the appropriate value. - -```js -const isArrayLike = val => { - try { - return [...val], true; - } catch (e) { - return false; - } -}; -``` - +### isArrayLike + +Checks if the provided argument is array-like (i.e. is iterable). + +Use the spread operator (`...`) to check if the provided argument is iterable inside a `try... catch` block and the comma operator (`,`) to return the appropriate value. + +```js +const isArrayLike = val => { + try { + return [...val], true; + } catch (e) { + return false; + } +}; +``` +
    Examples -```js -isArrayLike(document.querySelectorAll('.className')); // true -isArrayLike('abc'); // true -isArrayLike(null); // false -``` +```js +isArrayLike(document.querySelectorAll('.className')); // true +isArrayLike('abc'); // true +isArrayLike(null); // false +```

    [⬆ Back to top](#table-of-contents) -### isBoolean - -Checks if the given argument is a native boolean element. - -Use `typeof` to check if a value is classified as a boolean primitive. - -```js -const isBoolean = val => typeof val === 'boolean'; -``` - +### isBoolean + +Checks if the given argument is a native boolean element. + +Use `typeof` to check if a value is classified as a boolean primitive. + +```js +const isBoolean = val => typeof val === 'boolean'; +``` +
    Examples -```js -isBoolean(null); // false -isBoolean(false); // true -``` +```js +isBoolean(null); // false +isBoolean(false); // true +```

    [⬆ Back to top](#table-of-contents) -### isFunction - -Checks if the given argument is a function. - -Use `typeof` to check if a value is classified as a function primitive. - -```js -const isFunction = val => typeof val === 'function'; -``` - +### isFunction + +Checks if the given argument is a function. + +Use `typeof` to check if a value is classified as a function primitive. + +```js +const isFunction = val => typeof val === 'function'; +``` +
    Examples -```js -isFunction('x'); // false -isFunction(x => x); // true -``` +```js +isFunction('x'); // false +isFunction(x => x); // true +```

    [⬆ Back to top](#table-of-contents) -### isNull - -Returns `true` if the specified value is `null`, `false` otherwise. - -Use the strict equality operator to check if the value and of `val` are equal to `null`. - -```js -const isNull = val => val === null; -``` - +### isNull + +Returns `true` if the specified value is `null`, `false` otherwise. + +Use the strict equality operator to check if the value and of `val` are equal to `null`. + +```js +const isNull = val => val === null; +``` +
    Examples -```js -isNull(null); // true -``` +```js +isNull(null); // true +```

    [⬆ Back to top](#table-of-contents) -### isNumber - -Checks if the given argument is a number. - -Use `typeof` to check if a value is classified as a number primitive. - -```js -const isNumber = val => typeof val === 'number'; -``` - +### isNumber + +Checks if the given argument is a number. + +Use `typeof` to check if a value is classified as a number primitive. + +```js +const isNumber = val => typeof val === 'number'; +``` +
    Examples -```js -isNumber('1'); // false -isNumber(1); // true -``` +```js +isNumber('1'); // false +isNumber(1); // true +```

    [⬆ Back to top](#table-of-contents) -### isPrimitive - -Returns a boolean determining if the supplied value is primitive or not. - -Use `Array.includes()` on an array of type strings which are not primitive, -supplying the type using `typeof`. -Since `typeof null` evaluates to `'object'`, it needs to be directly compared. - -```js -const isPrimitive = val => !['object', 'function'].includes(typeof val) || val === null; -``` - +### isPrimitive + +Returns a boolean determining if the supplied value is primitive or not. + +Use `Array.includes()` on an array of type strings which are not primitive, +supplying the type using `typeof`. +Since `typeof null` evaluates to `'object'`, it needs to be directly compared. + +```js +const isPrimitive = val => !['object', 'function'].includes(typeof val) || val === null; +``` +
    Examples -```js -isPrimitive(null); // true -isPrimitive(50); // true -isPrimitive('Hello!'); // true -isPrimitive(false); // true -isPrimitive(Symbol()); // true -isPrimitive([]); // false -``` +```js +isPrimitive(null); // true +isPrimitive(50); // true +isPrimitive('Hello!'); // true +isPrimitive(false); // true +isPrimitive(Symbol()); // true +isPrimitive([]); // false +```

    [⬆ Back to top](#table-of-contents) -### isPromiseLike - -Returns `true` if an object looks like a [`Promise`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise), `false` otherwise. - -Check if the object is not `null`, its `typeof` matches either `object` or `function` and if it has a `.then` property, which is also a `function`. - -```js -const isPromiseLike = obj => - obj !== null && - (typeof obj === 'object' || typeof obj === 'function') && - typeof obj.then === 'function'; -``` - +### isPromiseLike + +Returns `true` if an object looks like a [`Promise`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise), `false` otherwise. + +Check if the object is not `null`, its `typeof` matches either `object` or `function` and if it has a `.then` property, which is also a `function`. + +```js +const isPromiseLike = obj => + obj !== null && + (typeof obj === 'object' || typeof obj === 'function') && + typeof obj.then === 'function'; +``` +
    Examples -```js -isPromiseLike({ - then: function() { - return ''; - } -}); // true -isPromiseLike(null); // false -isPromiseLike({}); // false -``` +```js +isPromiseLike({ + then: function() { + return ''; + } +}); // true +isPromiseLike(null); // false +isPromiseLike({}); // false +```

    [⬆ Back to top](#table-of-contents) -### isString - -Checks if the given argument is a string. - -Use `typeof` to check if a value is classified as a string primitive. - -```js -const isString = val => typeof val === 'string'; -``` - +### isString + +Checks if the given argument is a string. + +Use `typeof` to check if a value is classified as a string primitive. + +```js +const isString = val => typeof val === 'string'; +``` +
    Examples -```js -isString('10'); // true -``` +```js +isString('10'); // true +```

    [⬆ Back to top](#table-of-contents) -### isSymbol - -Checks if the given argument is a symbol. - -Use `typeof` to check if a value is classified as a symbol primitive. - -```js -const isSymbol = val => typeof val === 'symbol'; -``` - +### isSymbol + +Checks if the given argument is a symbol. + +Use `typeof` to check if a value is classified as a symbol primitive. + +```js +const isSymbol = val => typeof val === 'symbol'; +``` +
    Examples -```js -isSymbol(Symbol('x')); // true -``` +```js +isSymbol(Symbol('x')); // true +```

    [⬆ Back to top](#table-of-contents) -### isValidJSON - -Checks if the provided argument is a valid JSON. - -Use `JSON.parse()` and a `try... catch` block to check if the provided argument is a valid JSON. - -```js -const isValidJSON = obj => { - try { - JSON.parse(obj); - return true; - } catch (e) { - return false; - } -}; -``` - +### isValidJSON + +Checks if the provided argument is a valid JSON. + +Use `JSON.parse()` and a `try... catch` block to check if the provided argument is a valid JSON. + +```js +const isValidJSON = obj => { + try { + JSON.parse(obj); + return true; + } catch (e) { + return false; + } +}; +``` +
    Examples -```js -isValidJSON('{"name":"Adam","age":20}'); // true -isValidJSON('{"name":"Adam",age:"20"}'); // false -isValidJSON(null); // true -``` +```js +isValidJSON('{"name":"Adam","age":20}'); // true +isValidJSON('{"name":"Adam",age:"20"}'); // false +isValidJSON(null); // true +```
    @@ -4833,124 +4833,124 @@ isValidJSON(null); // true --- ## 🔧 Utility -### cloneRegExp - -Clones a regular expression. - -Use `new RegExp()`, `RegExp.source` and `RegExp.flags` to clone the given regular expression. - -```js -const cloneRegExp = regExp => new RegExp(regExp.source, regExp.flags); -``` - +### cloneRegExp + +Clones a regular expression. + +Use `new RegExp()`, `RegExp.source` and `RegExp.flags` to clone the given regular expression. + +```js +const cloneRegExp = regExp => new RegExp(regExp.source, regExp.flags); +``` +
    Examples -```js -const regExp = /lorem ipsum/gi; -const regExp2 = cloneRegExp(regExp); // /lorem ipsum/gi -``` +```js +const regExp = /lorem ipsum/gi; +const regExp2 = cloneRegExp(regExp); // /lorem ipsum/gi +```

    [⬆ Back to top](#table-of-contents) -### coalesce - -Returns the first non-null/undefined argument. - -Use `Array.find()` to return the first non `null`/`undefined` argument. - -```js -const coalesce = (...args) => args.find(_ => ![undefined, null].includes(_)); -``` - +### coalesce + +Returns the first non-null/undefined argument. + +Use `Array.find()` to return the first non `null`/`undefined` argument. + +```js +const coalesce = (...args) => args.find(_ => ![undefined, null].includes(_)); +``` +
    Examples -```js -coalesce(null, undefined, '', NaN, 'Waldo'); // "" -``` +```js +coalesce(null, undefined, '', NaN, 'Waldo'); // "" +```

    [⬆ Back to top](#table-of-contents) -### coalesceFactory - -Returns a customized coalesce function that returns the first argument that returns `true` from the provided argument validation function. - -Use `Array.find()` to return the first argument that returns `true` from the provided argument validation function. - -```js -const coalesceFactory = valid => (...args) => args.find(valid); -``` - +### coalesceFactory + +Returns a customized coalesce function that returns the first argument that returns `true` from the provided argument validation function. + +Use `Array.find()` to return the first argument that returns `true` from the provided argument validation function. + +```js +const coalesceFactory = valid => (...args) => args.find(valid); +``` +
    Examples -```js -const customCoalesce = coalesceFactory(_ => ![null, undefined, '', NaN].includes(_)); -customCoalesce(undefined, null, NaN, '', 'Waldo'); // "Waldo" -``` +```js +const customCoalesce = coalesceFactory(_ => ![null, undefined, '', NaN].includes(_)); +customCoalesce(undefined, null, NaN, '', 'Waldo'); // "Waldo" +```

    [⬆ Back to top](#table-of-contents) -### extendHex - -Extends a 3-digit color code to a 6-digit color code. - -Use `Array.map()`, `String.split()` and `Array.join()` to join the mapped array for converting a 3-digit RGB notated hexadecimal color-code to the 6-digit form. -`Array.slice()` is used to remove `#` from string start since it's added once. - -```js -const extendHex = shortHex => - '#' + - shortHex - .slice(shortHex.startsWith('#') ? 1 : 0) - .split('') - .map(x => x + x) - .join(''); -``` - +### extendHex + +Extends a 3-digit color code to a 6-digit color code. + +Use `Array.map()`, `String.split()` and `Array.join()` to join the mapped array for converting a 3-digit RGB notated hexadecimal color-code to the 6-digit form. +`Array.slice()` is used to remove `#` from string start since it's added once. + +```js +const extendHex = shortHex => + '#' + + shortHex + .slice(shortHex.startsWith('#') ? 1 : 0) + .split('') + .map(x => x + x) + .join(''); +``` +
    Examples -```js -extendHex('#03f'); // '#0033ff' -extendHex('05a'); // '#0055aa' -``` +```js +extendHex('#03f'); // '#0033ff' +extendHex('05a'); // '#0055aa' +```

    [⬆ Back to top](#table-of-contents) -### getURLParameters - -Returns an object containing the parameters of the current URL. - -Use `String.match()` with an appropriate regular expression to get all key-value pairs, `Array.reduce()` to map and combine them into a single object. -Pass `location.search` as the argument to apply to the current `url`. - -```js -const getURLParameters = url => - url - .match(/([^?=&]+)(=([^&]*))/g) - .reduce((a, v) => ((a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1)), a), {}); -``` - +### getURLParameters + +Returns an object containing the parameters of the current URL. + +Use `String.match()` with an appropriate regular expression to get all key-value pairs, `Array.reduce()` to map and combine them into a single object. +Pass `location.search` as the argument to apply to the current `url`. + +```js +const getURLParameters = url => + url + .match(/([^?=&]+)(=([^&]*))/g) + .reduce((a, v) => ((a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1)), a), {}); +``` +
    Examples -```js -getURLParameters('http://url.com/page?name=Adam&surname=Smith'); // {name: 'Adam', surname: 'Smith'} -``` +```js +getURLParameters('http://url.com/page?name=Adam&surname=Smith'); // {name: 'Adam', surname: 'Smith'} +```
    @@ -4999,226 +4999,226 @@ hexToRGB('#fff'); // 'rgb(255, 255, 255)'
    [⬆ Back to top](#table-of-contents) -### prettyBytes - -Converts a number in bytes to a human-readable string. - -Use an array dictionary of units to be accessed based on the exponent. -Use `Number.toPrecision()` to truncate the number to a certain number of digits. -Return the prettified string by building it up, taking into account the supplied options and whether it is negative or not. -Omit the second argument, `precision`, to use a default precision of `3` digits. -Omit the third argument, `addSpace`, to add space between the number and unit by default. - -```js -const prettyBytes = (num, precision = 3, addSpace = true) => { - const UNITS = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB']; - if (Math.abs(num) < 1) return num + (addSpace ? ' ' : '') + UNITS[0]; - const exponent = Math.min(Math.floor(Math.log10(num < 0 ? -num : num) / 3), UNITS.length - 1); - const n = Number(((num < 0 ? -num : num) / 1000 ** exponent).toPrecision(precision)); - return (num < 0 ? '-' : '') + n + (addSpace ? ' ' : '') + UNITS[exponent]; -}; -``` - +### prettyBytes + +Converts a number in bytes to a human-readable string. + +Use an array dictionary of units to be accessed based on the exponent. +Use `Number.toPrecision()` to truncate the number to a certain number of digits. +Return the prettified string by building it up, taking into account the supplied options and whether it is negative or not. +Omit the second argument, `precision`, to use a default precision of `3` digits. +Omit the third argument, `addSpace`, to add space between the number and unit by default. + +```js +const prettyBytes = (num, precision = 3, addSpace = true) => { + const UNITS = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB']; + if (Math.abs(num) < 1) return num + (addSpace ? ' ' : '') + UNITS[0]; + const exponent = Math.min(Math.floor(Math.log10(num < 0 ? -num : num) / 3), UNITS.length - 1); + const n = Number(((num < 0 ? -num : num) / 1000 ** exponent).toPrecision(precision)); + return (num < 0 ? '-' : '') + n + (addSpace ? ' ' : '') + UNITS[exponent]; +}; +``` +
    Examples -```js -prettyBytes(1000); // 1 KB -prettyBytes(-27145424323.5821, 5); // -27.145 GB -prettyBytes(123456789, 3, false); // 123MB -``` +```js +prettyBytes(1000); // 1 KB +prettyBytes(-27145424323.5821, 5); // -27.145 GB +prettyBytes(123456789, 3, false); // 123MB +```

    [⬆ Back to top](#table-of-contents) -### randomHexColorCode - -Generates a random hexadecimal color code. - -Use `Math.random` to generate a random 24-bit(6x4bits) hexadecimal number. Use bit shifting and then convert it to an hexadecimal String using `toString(16)`. - -```js -const randomHexColorCode = () => { - let n = ((Math.random() * 0xfffff) | 0).toString(16); - return '#' + (n.length !== 6 ? ((Math.random() * 0xf) | 0).toString(16) + n : n); -}; -``` - +### randomHexColorCode + +Generates a random hexadecimal color code. + +Use `Math.random` to generate a random 24-bit(6x4bits) hexadecimal number. Use bit shifting and then convert it to an hexadecimal String using `toString(16)`. + +```js +const randomHexColorCode = () => { + let n = ((Math.random() * 0xfffff) | 0).toString(16); + return '#' + (n.length !== 6 ? ((Math.random() * 0xf) | 0).toString(16) + n : n); +}; +``` +
    Examples -```js -randomHexColorCode(); // "#e34155" -``` +```js +randomHexColorCode(); // "#e34155" +```

    [⬆ Back to top](#table-of-contents) -### RGBToHex - -Converts the values of RGB components to a color code. - -Convert given RGB parameters to hexadecimal string using bitwise left-shift operator (`<<`) and `toString(16)`, then `String.padStart(6,'0')` to get a 6-digit hexadecimal value. - -```js -const RGBToHex = (r, g, b) => ((r << 16) + (g << 8) + b).toString(16).padStart(6, '0'); -``` - +### RGBToHex + +Converts the values of RGB components to a color code. + +Convert given RGB parameters to hexadecimal string using bitwise left-shift operator (`<<`) and `toString(16)`, then `String.padStart(6,'0')` to get a 6-digit hexadecimal value. + +```js +const RGBToHex = (r, g, b) => ((r << 16) + (g << 8) + b).toString(16).padStart(6, '0'); +``` +
    Examples -```js -RGBToHex(255, 165, 1); // 'ffa501' -``` +```js +RGBToHex(255, 165, 1); // 'ffa501' +```

    [⬆ Back to top](#table-of-contents) -### timeTaken - -Measures the time taken by a function to execute. - -Use `console.time()` and `console.timeEnd()` to measure the difference between the start and end times to determine how long the callback took to execute. - -```js -const timeTaken = callback => { - console.time('timeTaken'); - const r = callback(); - console.timeEnd('timeTaken'); - return r; -}; -``` - +### timeTaken + +Measures the time taken by a function to execute. + +Use `console.time()` and `console.timeEnd()` to measure the difference between the start and end times to determine how long the callback took to execute. + +```js +const timeTaken = callback => { + console.time('timeTaken'); + const r = callback(); + console.timeEnd('timeTaken'); + return r; +}; +``` +
    Examples -```js -timeTaken(() => Math.pow(2, 10)); // 1024, (logged): timeTaken: 0.02099609375ms -``` +```js +timeTaken(() => Math.pow(2, 10)); // 1024, (logged): timeTaken: 0.02099609375ms +```

    [⬆ Back to top](#table-of-contents) -### toDecimalMark - -Use `toLocaleString()` to convert a float-point arithmetic to the [Decimal mark](https://en.wikipedia.org/wiki/Decimal_mark) form. It makes a comma separated string from a number. - - ```js -const toDecimalMark = num => num.toLocaleString('en-US'); -``` - +### toDecimalMark + +Use `toLocaleString()` to convert a float-point arithmetic to the [Decimal mark](https://en.wikipedia.org/wiki/Decimal_mark) form. It makes a comma separated string from a number. + + ```js +const toDecimalMark = num => num.toLocaleString('en-US'); +``` +
    Examples -```js -toDecimalMark(12305030388.9087); // "12,305,030,388.9087" -``` +```js +toDecimalMark(12305030388.9087); // "12,305,030,388.9087" +```

    [⬆ Back to top](#table-of-contents) -### toOrdinalSuffix - -Adds an ordinal suffix to a number. - -Use the modulo operator (`%`) to find values of single and tens digits. -Find which ordinal pattern digits match. -If digit is found in teens pattern, use teens ordinal. - -```js -const toOrdinalSuffix = num => { - const int = parseInt(num), - digits = [int % 10, int % 100], - ordinals = ['st', 'nd', 'rd', 'th'], - oPattern = [1, 2, 3, 4], - tPattern = [11, 12, 13, 14, 15, 16, 17, 18, 19]; - return oPattern.includes(digits[0]) && !tPattern.includes(digits[1]) - ? int + ordinals[digits[0] - 1] - : int + ordinals[3]; -}; -``` - +### toOrdinalSuffix + +Adds an ordinal suffix to a number. + +Use the modulo operator (`%`) to find values of single and tens digits. +Find which ordinal pattern digits match. +If digit is found in teens pattern, use teens ordinal. + +```js +const toOrdinalSuffix = num => { + const int = parseInt(num), + digits = [int % 10, int % 100], + ordinals = ['st', 'nd', 'rd', 'th'], + oPattern = [1, 2, 3, 4], + tPattern = [11, 12, 13, 14, 15, 16, 17, 18, 19]; + return oPattern.includes(digits[0]) && !tPattern.includes(digits[1]) + ? int + ordinals[digits[0] - 1] + : int + ordinals[3]; +}; +``` +
    Examples -```js -toOrdinalSuffix('123'); // "123rd" -``` +```js +toOrdinalSuffix('123'); // "123rd" +```

    [⬆ Back to top](#table-of-contents) -### validateNumber - -Returns `true` if the given value is a number, `false` otherwise. - -Use `!isNaN()` in combination with `parseFloat()` to check if the argument is a number. -Use `isFinite()` to check if the number is finite. -Use `Number()` to check if the coercion holds. - -```js -const validateNumber = n => !isNaN(parseFloat(n)) && isFinite(n) && Number(n) == n; -``` - +### validateNumber + +Returns `true` if the given value is a number, `false` otherwise. + +Use `!isNaN()` in combination with `parseFloat()` to check if the argument is a number. +Use `isFinite()` to check if the number is finite. +Use `Number()` to check if the coercion holds. + +```js +const validateNumber = n => !isNaN(parseFloat(n)) && isFinite(n) && Number(n) == n; +``` +
    Examples -```js -validateNumber('10'); // true -``` +```js +validateNumber('10'); // true +```

    [⬆ Back to top](#table-of-contents) -### yesNo - -Returns `true` if the string is `y`/`yes` or `false` if the string is `n`/`no`. - -Use `RegExp.test()` to check if the string evaluates to `y/yes` or `n/no`. -Omit the second argument, `def` to set the default answer as `no`. - -```js -const yesNo = (val, def = false) => - /^(y|yes)$/i.test(val) ? true : /^(n|no)$/i.test(val) ? false : def; -``` - +### yesNo + +Returns `true` if the string is `y`/`yes` or `false` if the string is `n`/`no`. + +Use `RegExp.test()` to check if the string evaluates to `y/yes` or `n/no`. +Omit the second argument, `def` to set the default answer as `no`. + +```js +const yesNo = (val, def = false) => + /^(y|yes)$/i.test(val) ? true : /^(n|no)$/i.test(val) ? false : def; +``` +
    Examples -```js -yesNo('Y'); // true -yesNo('yes'); // true -yesNo('No'); // false -yesNo('Foo', true); // true -``` +```js +yesNo('Y'); // true +yesNo('yes'); // true +yesNo('No'); // false +yesNo('Foo', true); // true +```

    [⬆ Back to top](#table-of-contents) -## Collaborators - -| [](https://github.com/Chalarangelo)
    [Angelos Chalaris](https://github.com/Chalarangelo) | [](https://github.com/Pl4gue)
    [David Wu](https://github.com/Pl4gue) | [](https://github.com/fejes713)
    [Stefan Feješ](https://github.com/fejes713) | [](https://github.com/kingdavidmartins)
    [King David Martins](https://github.com/iamsoorena) | [](https://github.com/iamsoorena)
    [Soorena Soleimani](https://github.com/iamsoorena) | -| --- | --- | --- | --- | --- | -| [](https://github.com/elderhsouza)
    [Elder Henrique Souza](https://github.com/elderhsouza) | [](https://github.com/skatcat31)
    [Robert Mennell](https://github.com/skatcat31) | [](https://github.com/atomiks)
    [atomiks](https://github.com/atomiks) | - - -## Credits - -*Icons made by [Smashicons](https://www.flaticon.com/authors/smashicons) from [www.flaticon.com](https://www.flaticon.com/) is licensed by [CC 3.0 BY](http://creativecommons.org/licenses/by/3.0/).* +## Collaborators + +| [](https://github.com/Chalarangelo)
    [Angelos Chalaris](https://github.com/Chalarangelo) | [](https://github.com/Pl4gue)
    [David Wu](https://github.com/Pl4gue) | [](https://github.com/fejes713)
    [Stefan Feješ](https://github.com/fejes713) | [](https://github.com/kingdavidmartins)
    [King David Martins](https://github.com/iamsoorena) | [](https://github.com/iamsoorena)
    [Soorena Soleimani](https://github.com/iamsoorena) | +| --- | --- | --- | --- | --- | +| [](https://github.com/elderhsouza)
    [Elder Henrique Souza](https://github.com/elderhsouza) | [](https://github.com/skatcat31)
    [Robert Mennell](https://github.com/skatcat31) | [](https://github.com/atomiks)
    [atomiks](https://github.com/atomiks) | + + +## Credits + +*Icons made by [Smashicons](https://www.flaticon.com/authors/smashicons) from [www.flaticon.com](https://www.flaticon.com/) is licensed by [CC 3.0 BY](http://creativecommons.org/licenses/by/3.0/).* From d82dbb7ff8e8f646a2290b654c9a71da5581490d Mon Sep 17 00:00:00 2001 From: Enzo Volkmann Date: Mon, 8 Jan 2018 08:22:04 +0100 Subject: [PATCH 4/7] Added support for arrays and single strings --- snippets/longestString.md | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/snippets/longestString.md b/snippets/longestString.md index 03539dbe2..a7feb3c3d 100644 --- a/snippets/longestString.md +++ b/snippets/longestString.md @@ -1,16 +1,26 @@ ### longestString Takes an array of strings and returns the longest one. +The method also accepts combinations of single strings and string arrays Uses the [rest operator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters) to handle arrays as well as an indefinite amount of single arguments. Strings are compared using `Array.reduce()`. ```js -const longestString = (...strings) => [...strings].reduce((a, b) => a.length > b.length ? a : b); +const longestString = (...strings) => strings.map(str => { + if (Array.isArray(str)) { + const first = str.shift(); + strings.concat(str); + return first; + } else { + return str; + } + }).reduce((a, b) => a.length > b.length ? a : b); ``` ```js -longestString('this', 'is', 'a', 'testcase') // 'testcase' -longestString(['a', 'ab', 'abc']) // 'abc' +longestString('this', 'is', 'a', 'testcase'); // 'testcase' +longestString(['a', 'ab', 'abc']); // 'abc' +longestString(['a', 'ab', 'abc'], 'abcd'); // 'abcd' ``` From aaca35a220e15024ae1ccd7c3349b7a2011e8e0b Mon Sep 17 00:00:00 2001 From: Enzo Volkmann Date: Mon, 8 Jan 2018 20:33:47 +0100 Subject: [PATCH 5/7] Based on suggestions, added longestItem() --- snippets/longestItem.md | 17 +++++++++++++++++ snippets/longestString.md | 26 -------------------------- 2 files changed, 17 insertions(+), 26 deletions(-) create mode 100644 snippets/longestItem.md delete mode 100644 snippets/longestString.md diff --git a/snippets/longestItem.md b/snippets/longestItem.md new file mode 100644 index 000000000..31afe5bb9 --- /dev/null +++ b/snippets/longestItem.md @@ -0,0 +1,17 @@ +### longestItem + +Takes any iterable object or object with a `length` property and returns the longest one. + +The function sorts all arguments by their `length` and returns the first (longest) one. + +```js +const longestItem = (...vals) => [...vals].sort((a, b) => b.length - a.length)[0]; +``` + +```js +longestItem ('this', 'is', 'a', 'testcase'); // 'testcase' +longestItem (...['a', 'ab', 'abc']); // 'abc' +longestItem (...['a', 'ab', 'abc'], 'abcd'); // 'abcd' +longestItem([1, 2, 3], [1, 2], [1, 2, 3, 4, 5]); // [1, 2, 3, 4, 5] +longestItem([1, 2, 3], 'foobar'); // 'foobar' +``` diff --git a/snippets/longestString.md b/snippets/longestString.md deleted file mode 100644 index a7feb3c3d..000000000 --- a/snippets/longestString.md +++ /dev/null @@ -1,26 +0,0 @@ -### longestString - -Takes an array of strings and returns the longest one. -The method also accepts combinations of single strings and string arrays - -Uses the [rest operator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters) -to handle arrays as well as an indefinite amount of single arguments. -Strings are compared using `Array.reduce()`. - -```js -const longestString = (...strings) => strings.map(str => { - if (Array.isArray(str)) { - const first = str.shift(); - strings.concat(str); - return first; - } else { - return str; - } - }).reduce((a, b) => a.length > b.length ? a : b); -``` - -```js -longestString('this', 'is', 'a', 'testcase'); // 'testcase' -longestString(['a', 'ab', 'abc']); // 'abc' -longestString(['a', 'ab', 'abc'], 'abcd'); // 'abcd' -``` From cc71e26fc03d6649f915acbdab72d7f44b612c84 Mon Sep 17 00:00:00 2001 From: Enzo Volkmann Date: Mon, 8 Jan 2018 20:34:06 +0100 Subject: [PATCH 6/7] Revert "Updated README.md using `npm run builder`" This reverts commit 0c8de329cbcebb2ced3710fe72e5f052aaab5d24. --- README.md | 6066 ++++++++++++++++++++++++++--------------------------- 1 file changed, 3033 insertions(+), 3033 deletions(-) diff --git a/README.md b/README.md index 1cafb8550..79ba0b7b9 100644 --- a/README.md +++ b/README.md @@ -1,72 +1,72 @@ -![Logo](/logo.png) - -# 30 seconds of code - -[![License](https://img.shields.io/badge/license-CC0--1.0-blue.svg)](https://github.com/Chalarangelo/30-seconds-of-code/blob/master/LICENSE) [![npm Downloads](https://img.shields.io/npm/dt/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![npm Version](https://img.shields.io/npm/v/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![Gitter chat](https://img.shields.io/badge/chat-on%20gitter-4FB999.svg)](https://gitter.im/30-seconds-of-code/Lobby) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](http://makeapullrequest.com) [![Travis Build](https://travis-ci.org/Chalarangelo/30-seconds-of-code.svg?branch=master)](https://travis-ci.org/Chalarangelo/30-seconds-of-code) [![Insight.io](https://img.shields.io/badge/insight.io-Ready-brightgreen.svg)](https://insight.io/github.com/Chalarangelo/30-seconds-of-code/tree/master/?source=0) [![js-semistandard-style](https://img.shields.io/badge/code%20style-semistandard-brightgreen.svg)](https://github.com/Flet/semistandard) [![ProductHunt](https://img.shields.io/badge/producthunt-vote-orange.svg)](https://www.producthunt.com/posts/30-seconds-of-code) - - -> Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less. - - -- Use Ctrl + F or command + F to search for a snippet. -- Contributions welcome, please read the [contribution guide](CONTRIBUTING.md). -- Snippets are written in ES6, use the [Babel transpiler](https://babeljs.io/) to ensure backwards-compatibility. -- You can import these snippets into your text editor of choice (VSCode, Atom, Sublime) using the files found in [this repo](https://github.com/Rob-Rychs/30-seconds-of-code-texteditorsnippets). -- You can import these snippets into Alfred 3, using [this file](https://github.com/lslvxy/30-seconds-of-code-alfredsnippets). - -#### Package - -⚠️ **WARNING:** Snippets are not production ready. - -You can find a package with all the snippets on [npm](https://www.npmjs.com/package/30-seconds-of-code). - -``` -npm install 30-seconds-of-code -``` - -CDN links -- [ES2017 Full (UMD)](https://unpkg.com/30-seconds-of-code) -- [ES5 Minified (UMD)](https://unpkg.com/30-seconds-of-code/dist/_30s.es5.min.js) - -
    - -**Browser** - -> IMPORTANT: replace the `src` with the full version link and desired target spec (such as ES5 minified)): - -```html - - -``` - -**Node** - -```js -// CommonJS -const _30s = require('30-seconds-of-code'); -_30s.average(1, 2, 3); - -// ES Modules -import _30s from '30-seconds-of-code'; -_30s.average(1, 2, 3); -``` - -To import snippets directly: - -```js -// CommonJS -const { average } = require('30-seconds-of-code'); -average(1, 2, 3); - -// ES Modules -import { average } from '30-seconds-of-code'; -average(1, 2, 3); -``` -
    - -## Table of Contents +![Logo](/logo.png) + +# 30 seconds of code + +[![License](https://img.shields.io/badge/license-CC0--1.0-blue.svg)](https://github.com/Chalarangelo/30-seconds-of-code/blob/master/LICENSE) [![npm Downloads](https://img.shields.io/npm/dt/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![npm Version](https://img.shields.io/npm/v/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![Gitter chat](https://img.shields.io/badge/chat-on%20gitter-4FB999.svg)](https://gitter.im/30-seconds-of-code/Lobby) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](http://makeapullrequest.com) [![Travis Build](https://travis-ci.org/Chalarangelo/30-seconds-of-code.svg?branch=master)](https://travis-ci.org/Chalarangelo/30-seconds-of-code) [![Insight.io](https://img.shields.io/badge/insight.io-Ready-brightgreen.svg)](https://insight.io/github.com/Chalarangelo/30-seconds-of-code/tree/master/?source=0) [![js-semistandard-style](https://img.shields.io/badge/code%20style-semistandard-brightgreen.svg)](https://github.com/Flet/semistandard) [![ProductHunt](https://img.shields.io/badge/producthunt-vote-orange.svg)](https://www.producthunt.com/posts/30-seconds-of-code) + + +> Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less. + + +- Use Ctrl + F or command + F to search for a snippet. +- Contributions welcome, please read the [contribution guide](CONTRIBUTING.md). +- Snippets are written in ES6, use the [Babel transpiler](https://babeljs.io/) to ensure backwards-compatibility. +- You can import these snippets into your text editor of choice (VSCode, Atom, Sublime) using the files found in [this repo](https://github.com/Rob-Rychs/30-seconds-of-code-texteditorsnippets). +- You can import these snippets into Alfred 3, using [this file](https://github.com/lslvxy/30-seconds-of-code-alfredsnippets). + +#### Package + +⚠️ **WARNING:** Snippets are not production ready. + +You can find a package with all the snippets on [npm](https://www.npmjs.com/package/30-seconds-of-code). + +``` +npm install 30-seconds-of-code +``` + +CDN links +- [ES2017 Full (UMD)](https://unpkg.com/30-seconds-of-code) +- [ES5 Minified (UMD)](https://unpkg.com/30-seconds-of-code/dist/_30s.es5.min.js) + +
    + +**Browser** + +> IMPORTANT: replace the `src` with the full version link and desired target spec (such as ES5 minified)): + +```html + + +``` + +**Node** + +```js +// CommonJS +const _30s = require('30-seconds-of-code'); +_30s.average(1, 2, 3); + +// ES Modules +import _30s from '30-seconds-of-code'; +_30s.average(1, 2, 3); +``` + +To import snippets directly: + +```js +// CommonJS +const { average } = require('30-seconds-of-code'); +average(1, 2, 3); + +// ES Modules +import { average } from '30-seconds-of-code'; +average(1, 2, 3); +``` +
    + +## Table of Contents ### 🔌 Adapter @@ -430,55 +430,55 @@ Object.assign(b, a); // == b
    [⬆ Back to top](#table-of-contents) -### pipeFunctions - -Performs left-to-right function composition. - -Use `Array.reduce()` with the spread operator (`...`) to perform left-to-right function composition. -The first (leftmost) function can accept one or more arguments; the remaining functions must be unary. - -```js -const pipeFunctions = (...fns) => fns.reduce((f, g) => (...args) => g(f(...args))); -``` - +### pipeFunctions + +Performs left-to-right function composition. + +Use `Array.reduce()` with the spread operator (`...`) to perform left-to-right function composition. +The first (leftmost) function can accept one or more arguments; the remaining functions must be unary. + +```js +const pipeFunctions = (...fns) => fns.reduce((f, g) => (...args) => g(f(...args))); +``` +
    Examples -```js -const add5 = x => x + 5; -const multiply = (x, y) => x * y; -const multiplyAndAdd5 = pipeFunctions(multiply, add5); -multiplyAndAdd5(5, 2); // 15 -``` +```js +const add5 = x => x + 5; +const multiply = (x, y) => x * y; +const multiplyAndAdd5 = pipeFunctions(multiply, add5); +multiplyAndAdd5(5, 2); // 15 +```

    [⬆ Back to top](#table-of-contents) -### promisify - -Converts an asynchronous function to return a promise. - -Use currying to return a function returning a `Promise` that calls the original function. -Use the `...rest` operator to pass in all the parameters. - -*In Node 8+, you can use [`util.promisify`](https://nodejs.org/api/util.html#util_util_promisify_original)* - -```js -const promisify = func => (...args) => - new Promise((resolve, reject) => - func(...args, (err, result) => (err ? reject(err) : resolve(result))) - ); -``` - +### promisify + +Converts an asynchronous function to return a promise. + +Use currying to return a function returning a `Promise` that calls the original function. +Use the `...rest` operator to pass in all the parameters. + +*In Node 8+, you can use [`util.promisify`](https://nodejs.org/api/util.html#util_util_promisify_original)* + +```js +const promisify = func => (...args) => + new Promise((resolve, reject) => + func(...args, (err, result) => (err ? reject(err) : resolve(result))) + ); +``` +
    Examples -```js -const delay = promisify((d, cb) => setTimeout(cb, d)); -delay(2000).then(() => console.log('Hi!')); // // Promise resolves after 2s -``` +```js +const delay = promisify((d, cb) => setTimeout(cb, d)); +delay(2000).then(() => console.log('Hi!')); // // Promise resolves after 2s +```
    @@ -510,1214 +510,1214 @@ arrayMax([1, 2, 3]); // 3 --- ## 📚 Array -### chunk - -Chunks an array into smaller arrays of a specified size. - -Use `Array.from()` to create a new array, that fits the number of chunks that will be produced. -Use `Array.slice()` to map each element of the new array to a chunk the length of `size`. -If the original array can't be split evenly, the final chunk will contain the remaining elements. - -```js -const chunk = (arr, size) => - Array.from({ length: Math.ceil(arr.length / size) }, (v, i) => - arr.slice(i * size, i * size + size) - ); -``` - +### chunk + +Chunks an array into smaller arrays of a specified size. + +Use `Array.from()` to create a new array, that fits the number of chunks that will be produced. +Use `Array.slice()` to map each element of the new array to a chunk the length of `size`. +If the original array can't be split evenly, the final chunk will contain the remaining elements. + +```js +const chunk = (arr, size) => + Array.from({ length: Math.ceil(arr.length / size) }, (v, i) => + arr.slice(i * size, i * size + size) + ); +``` +
    Examples -```js -chunk([1, 2, 3, 4, 5], 2); // [[1,2],[3,4],[5]] -``` +```js +chunk([1, 2, 3, 4, 5], 2); // [[1,2],[3,4],[5]] +```

    [⬆ Back to top](#table-of-contents) -### compact - -Removes falsey values from an array. - -Use `Array.filter()` to filter out falsey values (`false`, `null`, `0`, `""`, `undefined`, and `NaN`). - -```js -const compact = arr => arr.filter(Boolean); -``` - +### compact + +Removes falsey values from an array. + +Use `Array.filter()` to filter out falsey values (`false`, `null`, `0`, `""`, `undefined`, and `NaN`). + +```js +const compact = arr => arr.filter(Boolean); +``` +
    Examples -```js -compact([0, 1, false, 2, '', 3, 'a', 'e' * 23, NaN, 's', 34]); // [ 1, 2, 3, 'a', 's', 34 ] -``` +```js +compact([0, 1, false, 2, '', 3, 'a', 'e' * 23, NaN, 's', 34]); // [ 1, 2, 3, 'a', 's', 34 ] +```

    [⬆ Back to top](#table-of-contents) -### countOccurrences - -Counts the occurrences of a value in an array. - -Use `Array.reduce()` to increment a counter each time you encounter the specific value inside the array. - -```js -const countOccurrences = (arr, val) => arr.reduce((a, v) => (v === val ? a + 1 : a + 0), 0); -``` - +### countOccurrences + +Counts the occurrences of a value in an array. + +Use `Array.reduce()` to increment a counter each time you encounter the specific value inside the array. + +```js +const countOccurrences = (arr, val) => arr.reduce((a, v) => (v === val ? a + 1 : a + 0), 0); +``` +
    Examples -```js -countOccurrences([1, 1, 2, 1, 2, 3], 1); // 3 -``` +```js +countOccurrences([1, 1, 2, 1, 2, 3], 1); // 3 +```

    [⬆ Back to top](#table-of-contents) -### deepFlatten - -Deep flattens an array. - -Use recursion. -Use `Array.concat()` with an empty array (`[]`) and the spread operator (`...`) to flatten an array. -Recursively flatten each element that is an array. - -```js -const deepFlatten = arr => [].concat(...arr.map(v => (Array.isArray(v) ? deepFlatten(v) : v))); -``` - +### deepFlatten + +Deep flattens an array. + +Use recursion. +Use `Array.concat()` with an empty array (`[]`) and the spread operator (`...`) to flatten an array. +Recursively flatten each element that is an array. + +```js +const deepFlatten = arr => [].concat(...arr.map(v => (Array.isArray(v) ? deepFlatten(v) : v))); +``` +
    Examples -```js -deepFlatten([1, [2], [[3], 4], 5]); // [1,2,3,4,5] -``` +```js +deepFlatten([1, [2], [[3], 4], 5]); // [1,2,3,4,5] +```

    [⬆ Back to top](#table-of-contents) -### difference - -Returns the difference between two arrays. - -Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values not contained in `b`. - -```js -const difference = (a, b) => { - const s = new Set(b); - return a.filter(x => !s.has(x)); -}; -``` - +### difference + +Returns the difference between two arrays. + +Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values not contained in `b`. + +```js +const difference = (a, b) => { + const s = new Set(b); + return a.filter(x => !s.has(x)); +}; +``` +
    Examples -```js -difference([1, 2, 3], [1, 2, 4]); // [3] -``` +```js +difference([1, 2, 3], [1, 2, 4]); // [3] +```

    [⬆ Back to top](#table-of-contents) -### differenceWith - -Filters out all values from an array for which the comparator function does not return `true`. - -Use `Array.filter()` and `Array.findIndex()` to find the appropriate values. - -```js -const differenceWith = (arr, val, comp) => arr.filter(a => val.findIndex(b => comp(a, b)) === -1); -``` - +### differenceWith + +Filters out all values from an array for which the comparator function does not return `true`. + +Use `Array.filter()` and `Array.findIndex()` to find the appropriate values. + +```js +const differenceWith = (arr, val, comp) => arr.filter(a => val.findIndex(b => comp(a, b)) === -1); +``` +
    Examples -```js -differenceWith([1, 1.2, 1.5, 3, 0], [1.9, 3, 0], (a, b) => Math.round(a) === Math.round(b)); // [1, 1.2] -``` +```js +differenceWith([1, 1.2, 1.5, 3, 0], [1.9, 3, 0], (a, b) => Math.round(a) === Math.round(b)); // [1, 1.2] +```

    [⬆ Back to top](#table-of-contents) -### distinctValuesOfArray - -Returns all the distinct values of an array. - -Use ES6 `Set` and the `...rest` operator to discard all duplicated values. - -```js -const distinctValuesOfArray = arr => [...new Set(arr)]; -``` - +### distinctValuesOfArray + +Returns all the distinct values of an array. + +Use ES6 `Set` and the `...rest` operator to discard all duplicated values. + +```js +const distinctValuesOfArray = arr => [...new Set(arr)]; +``` +
    Examples -```js -distinctValuesOfArray([1, 2, 2, 3, 4, 4, 5]); // [1,2,3,4,5] -``` +```js +distinctValuesOfArray([1, 2, 2, 3, 4, 4, 5]); // [1,2,3,4,5] +```

    [⬆ Back to top](#table-of-contents) -### dropElements - -Removes elements in an array until the passed function returns `true`. Returns the remaining elements in the array. - -Loop through the array, using `Array.slice()` to drop the first element of the array until the returned value from the function is `true`. -Returns the remaining elements. - -```js -const dropElements = (arr, func) => { - while (arr.length > 0 && !func(arr[0])) arr = arr.slice(1); - return arr; -}; -``` - +### dropElements + +Removes elements in an array until the passed function returns `true`. Returns the remaining elements in the array. + +Loop through the array, using `Array.slice()` to drop the first element of the array until the returned value from the function is `true`. +Returns the remaining elements. + +```js +const dropElements = (arr, func) => { + while (arr.length > 0 && !func(arr[0])) arr = arr.slice(1); + return arr; +}; +``` +
    Examples -```js -dropElements([1, 2, 3, 4], n => n >= 3); // [3,4] -``` +```js +dropElements([1, 2, 3, 4], n => n >= 3); // [3,4] +```

    [⬆ Back to top](#table-of-contents) -### dropRight - -Returns a new array with `n` elements removed from the right. - -Use `Array.slice()` to slice the remove the specified number of elements from the right. - -```js -const dropRight = (arr, n = 1) => arr.slice(0, -n); -``` - +### dropRight + +Returns a new array with `n` elements removed from the right. + +Use `Array.slice()` to slice the remove the specified number of elements from the right. + +```js +const dropRight = (arr, n = 1) => arr.slice(0, -n); +``` +
    Examples -```js -dropRight([1, 2, 3]); // [1,2] -dropRight([1, 2, 3], 2); // [1] -dropRight([1, 2, 3], 42); // [] -``` +```js +dropRight([1, 2, 3]); // [1,2] +dropRight([1, 2, 3], 2); // [1] +dropRight([1, 2, 3], 42); // [] +```

    [⬆ Back to top](#table-of-contents) -### everyNth - -Returns every nth element in an array. - -Use `Array.filter()` to create a new array that contains every nth element of a given array. - -```js -const everyNth = (arr, nth) => arr.filter((e, i) => i % nth === nth - 1); -``` - +### everyNth + +Returns every nth element in an array. + +Use `Array.filter()` to create a new array that contains every nth element of a given array. + +```js +const everyNth = (arr, nth) => arr.filter((e, i) => i % nth === nth - 1); +``` +
    Examples -```js -everyNth([1, 2, 3, 4, 5, 6], 2); // [ 2, 4, 6 ] -``` +```js +everyNth([1, 2, 3, 4, 5, 6], 2); // [ 2, 4, 6 ] +```

    [⬆ Back to top](#table-of-contents) -### filterNonUnique - -Filters out the non-unique values in an array. - -Use `Array.filter()` for an array containing only the unique values. - -```js -const filterNonUnique = arr => arr.filter(i => arr.indexOf(i) === arr.lastIndexOf(i)); -``` - +### filterNonUnique + +Filters out the non-unique values in an array. + +Use `Array.filter()` for an array containing only the unique values. + +```js +const filterNonUnique = arr => arr.filter(i => arr.indexOf(i) === arr.lastIndexOf(i)); +``` +
    Examples -```js -filterNonUnique([1, 2, 2, 3, 4, 4, 5]); // [1,3,5] -``` +```js +filterNonUnique([1, 2, 2, 3, 4, 4, 5]); // [1,3,5] +```

    [⬆ Back to top](#table-of-contents) -### flatten - -Flattens an array. - -Use a new array, `Array.concat()` and the spread operator (`...`) to cause a shallow denesting of any contained arrays. - -```js -const flatten = arr => [].concat(...arr); -``` - +### flatten + +Flattens an array. + +Use a new array, `Array.concat()` and the spread operator (`...`) to cause a shallow denesting of any contained arrays. + +```js +const flatten = arr => [].concat(...arr); +``` +
    Examples -```js -flatten([1, [2], 3, 4]); // [1,2,3,4] -``` +```js +flatten([1, [2], 3, 4]); // [1,2,3,4] +```

    [⬆ Back to top](#table-of-contents) -### flattenDepth - -Flattens an array up to the specified depth. - -Use recursion, decrementing `depth` by 1 for each level of depth. -Use `Array.reduce()` and `Array.concat()` to merge elements or arrays. -Base case, for `depth` equal to `1` stops recursion. -Omit the second element, `depth` to flatten only to a depth of `1` (single flatten). - -```js -const flattenDepth = (arr, depth = 1) => - depth != 1 - ? arr.reduce((a, v) => a.concat(Array.isArray(v) ? flattenDepth(v, depth - 1) : v), []) - : arr.reduce((a, v) => a.concat(v), []); -``` - +### flattenDepth + +Flattens an array up to the specified depth. + +Use recursion, decrementing `depth` by 1 for each level of depth. +Use `Array.reduce()` and `Array.concat()` to merge elements or arrays. +Base case, for `depth` equal to `1` stops recursion. +Omit the second element, `depth` to flatten only to a depth of `1` (single flatten). + +```js +const flattenDepth = (arr, depth = 1) => + depth != 1 + ? arr.reduce((a, v) => a.concat(Array.isArray(v) ? flattenDepth(v, depth - 1) : v), []) + : arr.reduce((a, v) => a.concat(v), []); +``` +
    Examples -```js -flattenDepth([1, [2], 3, 4]); // [1,2,3,4] -``` +```js +flattenDepth([1, [2], 3, 4]); // [1,2,3,4] +```

    [⬆ Back to top](#table-of-contents) -### groupBy - -Groups the elements of an array based on the given function. - -Use `Array.map()` to map the values of an array to a function or property name. -Use `Array.reduce()` to create an object, where the keys are produced from the mapped results. - -```js -const groupBy = (arr, func) => - arr.map(typeof func === 'function' ? func : val => val[func]).reduce((acc, val, i) => { - acc[val] = (acc[val] || []).concat(arr[i]); - return acc; - }, {}); -``` - +### groupBy + +Groups the elements of an array based on the given function. + +Use `Array.map()` to map the values of an array to a function or property name. +Use `Array.reduce()` to create an object, where the keys are produced from the mapped results. + +```js +const groupBy = (arr, func) => + arr.map(typeof func === 'function' ? func : val => val[func]).reduce((acc, val, i) => { + acc[val] = (acc[val] || []).concat(arr[i]); + return acc; + }, {}); +``` +
    Examples -```js -groupBy([6.1, 4.2, 6.3], Math.floor); // {4: [4.2], 6: [6.1, 6.3]} -groupBy(['one', 'two', 'three'], 'length'); // {3: ['one', 'two'], 5: ['three']} -``` +```js +groupBy([6.1, 4.2, 6.3], Math.floor); // {4: [4.2], 6: [6.1, 6.3]} +groupBy(['one', 'two', 'three'], 'length'); // {3: ['one', 'two'], 5: ['three']} +```

    [⬆ Back to top](#table-of-contents) -### head - -Returns the head of a list. - -Use `arr[0]` to return the first element of the passed array. - -```js -const head = arr => arr[0]; -``` - +### head + +Returns the head of a list. + +Use `arr[0]` to return the first element of the passed array. + +```js +const head = arr => arr[0]; +``` +
    Examples -```js -head([1, 2, 3]); // 1 -``` +```js +head([1, 2, 3]); // 1 +```

    [⬆ Back to top](#table-of-contents) -### indexOfAll - -Returns all indices of `val` in an array. If `val` never occurs, returns `[-1]`. - -Use `Array.forEach()` to loop over elements and `Array.push()` to store indices for matching elements. -Return `[-1]` if `length` of the array of indices is `0`, otherwise return the array of indices. - -```js -const indexOfAll = (arr, val) => { - const indices = []; - arr.forEach((el, i) => el === val && indices.push(i)); - return indices.length ? indices : [-1]; -}; -``` - +### indexOfAll + +Returns all indices of `val` in an array. If `val` never occurs, returns `[-1]`. + +Use `Array.forEach()` to loop over elements and `Array.push()` to store indices for matching elements. +Return `[-1]` if `length` of the array of indices is `0`, otherwise return the array of indices. + +```js +const indexOfAll = (arr, val) => { + const indices = []; + arr.forEach((el, i) => el === val && indices.push(i)); + return indices.length ? indices : [-1]; +}; +``` +
    Examples -```js -indexOfAll([1, 2, 3, 1, 2, 3], 1); // [0,3] -indexOfAll([1, 2, 3], 4); // [-1] -``` +```js +indexOfAll([1, 2, 3, 1, 2, 3], 1); // [0,3] +indexOfAll([1, 2, 3], 4); // [-1] +```

    [⬆ Back to top](#table-of-contents) -### initial - -Returns all the elements of an array except the last one. - -Use `arr.slice(0,-1)` to return all but the last element of the array. - -```js -const initial = arr => arr.slice(0, -1); -``` - +### initial + +Returns all the elements of an array except the last one. + +Use `arr.slice(0,-1)` to return all but the last element of the array. + +```js +const initial = arr => arr.slice(0, -1); +``` +
    Examples -```js -initial([1, 2, 3]); // [1,2] -``` +```js +initial([1, 2, 3]); // [1,2] +```

    [⬆ Back to top](#table-of-contents) -### initialize2DArray - -Initializes a 2D array of given width and height and value. - -Use `Array.map()` to generate h rows where each is a new array of size w initialize with value. If the value is not provided, default to `null`. - -```js -const initialize2DArray = (w, h, val = null) => - Array(h) - .fill() - .map(() => Array(w).fill(val)); -``` - +### initialize2DArray + +Initializes a 2D array of given width and height and value. + +Use `Array.map()` to generate h rows where each is a new array of size w initialize with value. If the value is not provided, default to `null`. + +```js +const initialize2DArray = (w, h, val = null) => + Array(h) + .fill() + .map(() => Array(w).fill(val)); +``` +
    Examples -```js -initialize2DArray(2, 2, 0); // [[0,0], [0,0]] -``` +```js +initialize2DArray(2, 2, 0); // [[0,0], [0,0]] +```

    [⬆ Back to top](#table-of-contents) -### initializeArrayWithRange - -Initializes an array containing the numbers in the specified range where `start` and `end` are inclusive with there common difference `step`. - -Use `Array.from(Math.ceil((end+1-start)/step))` to create an array of the desired length(the amounts of elements is equal to `(end-start)/step` or `(end+1-start)/step` for inclusive end), `Array.map()` to fill with the desired values in a range. -You can omit `start` to use a default value of `0`. -You can omit `step` to use a default value of `1`. - -```js -const initializeArrayWithRange = (end, start = 0, step = 1) => - Array.from({ length: Math.ceil((end + 1 - start) / step) }).map((v, i) => i * step + start); -``` - +### initializeArrayWithRange + +Initializes an array containing the numbers in the specified range where `start` and `end` are inclusive with there common difference `step`. + +Use `Array.from(Math.ceil((end+1-start)/step))` to create an array of the desired length(the amounts of elements is equal to `(end-start)/step` or `(end+1-start)/step` for inclusive end), `Array.map()` to fill with the desired values in a range. +You can omit `start` to use a default value of `0`. +You can omit `step` to use a default value of `1`. + +```js +const initializeArrayWithRange = (end, start = 0, step = 1) => + Array.from({ length: Math.ceil((end + 1 - start) / step) }).map((v, i) => i * step + start); +``` +
    Examples -```js -initializeArrayWithRange(5); // [0,1,2,3,4,5] -initializeArrayWithRange(7, 3); // [3,4,5,6,7] -initializeArrayWithRange(9, 0, 2); // [0,2,4,6,8] -``` +```js +initializeArrayWithRange(5); // [0,1,2,3,4,5] +initializeArrayWithRange(7, 3); // [3,4,5,6,7] +initializeArrayWithRange(9, 0, 2); // [0,2,4,6,8] +```

    [⬆ Back to top](#table-of-contents) -### initializeArrayWithValues - -Initializes and fills an array with the specified values. - -Use `Array(n)` to create an array of the desired length, `fill(v)` to fill it with the desired values. -You can omit `val` to use a default value of `0`. - -```js -const initializeArrayWithValues = (n, val = 0) => Array(n).fill(val); -``` - +### initializeArrayWithValues + +Initializes and fills an array with the specified values. + +Use `Array(n)` to create an array of the desired length, `fill(v)` to fill it with the desired values. +You can omit `val` to use a default value of `0`. + +```js +const initializeArrayWithValues = (n, val = 0) => Array(n).fill(val); +``` +
    Examples -```js -initializeArrayWithValues(5, 2); // [2,2,2,2,2] -``` +```js +initializeArrayWithValues(5, 2); // [2,2,2,2,2] +```

    [⬆ Back to top](#table-of-contents) -### intersection - -Returns a list of elements that exist in both arrays. - -Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values contained in `b`. - -```js -const intersection = (a, b) => { - const s = new Set(b); - return a.filter(x => s.has(x)); -}; -``` - +### intersection + +Returns a list of elements that exist in both arrays. + +Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values contained in `b`. + +```js +const intersection = (a, b) => { + const s = new Set(b); + return a.filter(x => s.has(x)); +}; +``` +
    Examples -```js -intersection([1, 2, 3], [4, 3, 2]); // [2,3] -``` +```js +intersection([1, 2, 3], [4, 3, 2]); // [2,3] +```

    [⬆ Back to top](#table-of-contents) -### isSorted - -Returns `1` if the array is sorted in ascending order, `-1` if it is sorted in descending order or `0` if it is not sorted. - -Calculate the ordering `direction` for the first two elements. -Use `Object.entries()` to loop over array objects and compare them in pairs. -Return `0` if the `direction` changes or the `direction` if the last element is reached. - -```js -const isSorted = arr => { - const direction = arr[0] > arr[1] ? -1 : 1; - for (let [i, val] of arr.entries()) - if (i === arr.length - 1) return direction; - else if ((val - arr[i + 1]) * direction > 0) return 0; -}; -``` - +### isSorted + +Returns `1` if the array is sorted in ascending order, `-1` if it is sorted in descending order or `0` if it is not sorted. + +Calculate the ordering `direction` for the first two elements. +Use `Object.entries()` to loop over array objects and compare them in pairs. +Return `0` if the `direction` changes or the `direction` if the last element is reached. + +```js +const isSorted = arr => { + const direction = arr[0] > arr[1] ? -1 : 1; + for (let [i, val] of arr.entries()) + if (i === arr.length - 1) return direction; + else if ((val - arr[i + 1]) * direction > 0) return 0; +}; +``` +
    Examples -```js -isSorted([0, 1, 2, 2]); // 1 -isSorted([4, 3, 2]); // -1 -isSorted([4, 3, 5]); // 0 -``` +```js +isSorted([0, 1, 2, 2]); // 1 +isSorted([4, 3, 2]); // -1 +isSorted([4, 3, 5]); // 0 +```

    [⬆ Back to top](#table-of-contents) -### join - -Joins all elements of an array into a string and returns this string. Uses a separator and an end separator. - -Use `Array.reduce()` to combine elements into a string. -Omit the second argument, `separator`, to use a default separator of `','`. -Omit the third argument, `end`, to use the same value as `separator` by default. - -```js -const join = (arr, separator = ',', end = separator) => - arr.reduce( - (acc, val, i) => - i == arr.length - 2 - ? acc + val + end - : i == arr.length - 1 ? acc + val : acc + val + separator, - '' - ); -``` - +### join + +Joins all elements of an array into a string and returns this string. Uses a separator and an end separator. + +Use `Array.reduce()` to combine elements into a string. +Omit the second argument, `separator`, to use a default separator of `','`. +Omit the third argument, `end`, to use the same value as `separator` by default. + +```js +const join = (arr, separator = ',', end = separator) => + arr.reduce( + (acc, val, i) => + i == arr.length - 2 + ? acc + val + end + : i == arr.length - 1 ? acc + val : acc + val + separator, + '' + ); +``` +
    Examples -```js -join(['pen', 'pineapple', 'apple', 'pen'], ',', '&'); // "pen,pineapple,apple&pen" -join(['pen', 'pineapple', 'apple', 'pen'], ','); // "pen,pineapple,apple,pen" -join(['pen', 'pineapple', 'apple', 'pen']); // "pen,pineapple,apple,pen" -``` +```js +join(['pen', 'pineapple', 'apple', 'pen'], ',', '&'); // "pen,pineapple,apple&pen" +join(['pen', 'pineapple', 'apple', 'pen'], ','); // "pen,pineapple,apple,pen" +join(['pen', 'pineapple', 'apple', 'pen']); // "pen,pineapple,apple,pen" +```

    [⬆ Back to top](#table-of-contents) -### last - -Returns the last element in an array. - -Use `arr.length - 1` to compute the index of the last element of the given array and returning it. - -```js -const last = arr => arr[arr.length - 1]; -``` - +### last + +Returns the last element in an array. + +Use `arr.length - 1` to compute the index of the last element of the given array and returning it. + +```js +const last = arr => arr[arr.length - 1]; +``` +
    Examples -```js -last([1, 2, 3]); // 3 -``` +```js +last([1, 2, 3]); // 3 +```

    [⬆ Back to top](#table-of-contents) -### mapObject - -Maps the values of an array to an object using a function, where the key-value pairs consist of the original value as the key and the mapped value. - -Use an anonymous inner function scope to declare an undefined memory space, using closures to store a return value. Use a new `Array` to store the array with a map of the function over its data set and a comma operator to return a second step, without needing to move from one context to another (due to closures and order of operations). - -```js -const mapObject = (arr, fn) => - (a => ( - (a = [arr, arr.map(fn)]), a[0].reduce((acc, val, ind) => ((acc[val] = a[1][ind]), acc), {}) - ))(); -``` - +### mapObject + +Maps the values of an array to an object using a function, where the key-value pairs consist of the original value as the key and the mapped value. + +Use an anonymous inner function scope to declare an undefined memory space, using closures to store a return value. Use a new `Array` to store the array with a map of the function over its data set and a comma operator to return a second step, without needing to move from one context to another (due to closures and order of operations). + +```js +const mapObject = (arr, fn) => + (a => ( + (a = [arr, arr.map(fn)]), a[0].reduce((acc, val, ind) => ((acc[val] = a[1][ind]), acc), {}) + ))(); +``` +
    Examples -```js -const squareIt = arr => mapObject(arr, a => a * a); -squareIt([1, 2, 3]); // { 1: 1, 2: 4, 3: 9 } -``` +```js +const squareIt = arr => mapObject(arr, a => a * a); +squareIt([1, 2, 3]); // { 1: 1, 2: 4, 3: 9 } +```

    [⬆ Back to top](#table-of-contents) -### maxN - -Returns the `n` maximum elements from the provided array. If `n` is greater than or equal to the provided array's length, then return the original array(sorted in descending order). - -Use `Array.sort()` combined with the spread operator (`...`) to create a shallow clone of the array and sort it in descending order. -Use `Array.slice()` to get the specified number of elements. -Omit the second argument, `n`, to get a one-element array. - -```js -const maxN = (arr, n = 1) => [...arr].sort((a, b) => b - a).slice(0, n); -``` - +### maxN + +Returns the `n` maximum elements from the provided array. If `n` is greater than or equal to the provided array's length, then return the original array(sorted in descending order). + +Use `Array.sort()` combined with the spread operator (`...`) to create a shallow clone of the array and sort it in descending order. +Use `Array.slice()` to get the specified number of elements. +Omit the second argument, `n`, to get a one-element array. + +```js +const maxN = (arr, n = 1) => [...arr].sort((a, b) => b - a).slice(0, n); +``` +
    Examples -```js -maxN([1, 2, 3]); // [3] -maxN([1, 2, 3], 2); // [3,2] -``` +```js +maxN([1, 2, 3]); // [3] +maxN([1, 2, 3], 2); // [3,2] +```

    [⬆ Back to top](#table-of-contents) -### minN - -Returns the `n` minimum elements from the provided array. If `n` is greater than or equal to the provided array's length, then return the original array(sorted in ascending order). - -Use `Array.sort()` combined with the spread operator (`...`) to create a shallow clone of the array and sort it in ascending order. -Use `Array.slice()` to get the specified number of elements. -Omit the second argument, `n`, to get a one-element array. - -```js -const minN = (arr, n = 1) => [...arr].sort((a, b) => a - b).slice(0, n); -``` +### minN + +Returns the `n` minimum elements from the provided array. If `n` is greater than or equal to the provided array's length, then return the original array(sorted in ascending order). + +Use `Array.sort()` combined with the spread operator (`...`) to create a shallow clone of the array and sort it in ascending order. +Use `Array.slice()` to get the specified number of elements. +Omit the second argument, `n`, to get a one-element array. + +```js +const minN = (arr, n = 1) => [...arr].sort((a, b) => a - b).slice(0, n); +```
    Examples -```js -minN([1, 2, 3]); // [1] -minN([1, 2, 3], 2); // [1,2] -``` +```js +minN([1, 2, 3]); // [1] +minN([1, 2, 3], 2); // [1,2] +```

    [⬆ Back to top](#table-of-contents) -### nthElement - -Returns the nth element of an array. - -Use `Array.slice()` to get an array containing the nth element at the first place. -If the index is out of bounds, return `[]`. -Omit the second argument, `n`, to get the first element of the array. - -```js -const nthElement = (arr, n = 0) => (n > 0 ? arr.slice(n, n + 1) : arr.slice(n))[0]; -``` - +### nthElement + +Returns the nth element of an array. + +Use `Array.slice()` to get an array containing the nth element at the first place. +If the index is out of bounds, return `[]`. +Omit the second argument, `n`, to get the first element of the array. + +```js +const nthElement = (arr, n = 0) => (n > 0 ? arr.slice(n, n + 1) : arr.slice(n))[0]; +``` +
    Examples -```js -nthElement(['a', 'b', 'c'], 1); // 'b' -nthElement(['a', 'b', 'b'], -3); // 'a' -``` +```js +nthElement(['a', 'b', 'c'], 1); // 'b' +nthElement(['a', 'b', 'b'], -3); // 'a' +```

    [⬆ Back to top](#table-of-contents) -### pick - -Picks the key-value pairs corresponding to the given keys from an object. - -Use `Array.reduce()` to convert the filtered/picked keys back to an object with the corresponding key-value pair if the key exists in the obj. - -```js -const pick = (obj, arr) => - arr.reduce((acc, curr) => (curr in obj && (acc[curr] = obj[curr]), acc), {}); -``` - +### pick + +Picks the key-value pairs corresponding to the given keys from an object. + +Use `Array.reduce()` to convert the filtered/picked keys back to an object with the corresponding key-value pair if the key exists in the obj. + +```js +const pick = (obj, arr) => + arr.reduce((acc, curr) => (curr in obj && (acc[curr] = obj[curr]), acc), {}); +``` +
    Examples -```js -pick({ a: 1, b: '2', c: 3 }, ['a', 'c']); // { 'a': 1, 'c': 3 } -``` +```js +pick({ a: 1, b: '2', c: 3 }, ['a', 'c']); // { 'a': 1, 'c': 3 } +```

    [⬆ Back to top](#table-of-contents) -### pull - -Mutates the original array to filter out the values specified. - -Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed. -Use `Array.length = 0` to mutate the passed in an array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values. - -_(For a snippet that does not mutate the original array see [`without`](#without))_ - -```js -const pull = (arr, ...args) => { - let argState = Array.isArray(args[0]) ? args[0] : args; - let pulled = arr.filter((v, i) => !argState.includes(v)); - arr.length = 0; - pulled.forEach(v => arr.push(v)); -}; -``` - +### pull + +Mutates the original array to filter out the values specified. + +Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed. +Use `Array.length = 0` to mutate the passed in an array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values. + +_(For a snippet that does not mutate the original array see [`without`](#without))_ + +```js +const pull = (arr, ...args) => { + let argState = Array.isArray(args[0]) ? args[0] : args; + let pulled = arr.filter((v, i) => !argState.includes(v)); + arr.length = 0; + pulled.forEach(v => arr.push(v)); +}; +``` +
    Examples -```js -let myArray = ['a', 'b', 'c', 'a', 'b', 'c']; -pull(myArray, 'a', 'c'); // myArray = [ 'b', 'b' ] -``` +```js +let myArray = ['a', 'b', 'c', 'a', 'b', 'c']; +pull(myArray, 'a', 'c'); // myArray = [ 'b', 'b' ] +```

    [⬆ Back to top](#table-of-contents) -### pullAtIndex - -Mutates the original array to filter out the values at the specified indexes. - -Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed. -Use `Array.length = 0` to mutate the passed in an array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values. -Use `Array.push()` to keep track of pulled values - -```js -const pullAtIndex = (arr, pullArr) => { - let removed = []; - let pulled = arr - .map((v, i) => (pullArr.includes(i) ? removed.push(v) : v)) - .filter((v, i) => !pullArr.includes(i)); - arr.length = 0; - pulled.forEach(v => arr.push(v)); - return removed; -}; -``` - +### pullAtIndex + +Mutates the original array to filter out the values at the specified indexes. + +Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed. +Use `Array.length = 0` to mutate the passed in an array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values. +Use `Array.push()` to keep track of pulled values + +```js +const pullAtIndex = (arr, pullArr) => { + let removed = []; + let pulled = arr + .map((v, i) => (pullArr.includes(i) ? removed.push(v) : v)) + .filter((v, i) => !pullArr.includes(i)); + arr.length = 0; + pulled.forEach(v => arr.push(v)); + return removed; +}; +``` +
    Examples -```js -let myArray = ['a', 'b', 'c', 'd']; -let pulled = pullAtIndex(myArray, [1, 3]); // myArray = [ 'a', 'c' ] , pulled = [ 'b', 'd' ] -``` +```js +let myArray = ['a', 'b', 'c', 'd']; +let pulled = pullAtIndex(myArray, [1, 3]); // myArray = [ 'a', 'c' ] , pulled = [ 'b', 'd' ] +```

    [⬆ Back to top](#table-of-contents) -### pullAtValue - -Mutates the original array to filter out the values specified. Returns the removed elements. - -Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed. -Use `Array.length = 0` to mutate the passed in an array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values. -Use `Array.push()` to keep track of pulled values - -```js -const pullAtValue = (arr, pullArr) => { - let removed = [], - pushToRemove = arr.forEach((v, i) => (pullArr.includes(v) ? removed.push(v) : v)), - mutateTo = arr.filter((v, i) => !pullArr.includes(v)); - arr.length = 0; - mutateTo.forEach(v => arr.push(v)); - return removed; -}; -``` - +### pullAtValue + +Mutates the original array to filter out the values specified. Returns the removed elements. + +Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed. +Use `Array.length = 0` to mutate the passed in an array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values. +Use `Array.push()` to keep track of pulled values + +```js +const pullAtValue = (arr, pullArr) => { + let removed = [], + pushToRemove = arr.forEach((v, i) => (pullArr.includes(v) ? removed.push(v) : v)), + mutateTo = arr.filter((v, i) => !pullArr.includes(v)); + arr.length = 0; + mutateTo.forEach(v => arr.push(v)); + return removed; +}; +``` +
    Examples -```js -let myArray = ['a', 'b', 'c', 'd']; -let pulled = pullAtValue(myArray, ['b', 'd']); // myArray = [ 'a', 'c' ] , pulled = [ 'b', 'd' ] -``` +```js +let myArray = ['a', 'b', 'c', 'd']; +let pulled = pullAtValue(myArray, ['b', 'd']); // myArray = [ 'a', 'c' ] , pulled = [ 'b', 'd' ] +```

    [⬆ Back to top](#table-of-contents) -### reducedFilter - -Filter an array of objects based on a condition while also filtering out unspecified keys. - -Use `Array.filter()` to filter the array based on the predicate `fn` so that it returns the objects for which the condition returned a truthy value. -On the filtered array, use `Array.map()` to return the new object using `Array.reduce()` to filter out the keys which were not supplied as the `keys` argument. - -```js -const reducedFilter = (data, keys, fn) => - data.filter(fn).map(el => - keys.reduce((acc, key) => { - acc[key] = el[key]; - return acc; - }, {}) - ); -``` - +### reducedFilter + +Filter an array of objects based on a condition while also filtering out unspecified keys. + +Use `Array.filter()` to filter the array based on the predicate `fn` so that it returns the objects for which the condition returned a truthy value. +On the filtered array, use `Array.map()` to return the new object using `Array.reduce()` to filter out the keys which were not supplied as the `keys` argument. + +```js +const reducedFilter = (data, keys, fn) => + data.filter(fn).map(el => + keys.reduce((acc, key) => { + acc[key] = el[key]; + return acc; + }, {}) + ); +``` +
    Examples -```js -const data = [ - { - id: 1, - name: 'john', - age: 24 - }, - { - id: 2, - name: 'mike', - age: 50 - } -]; - -reducedFilter(data, ['id', 'name'], item => item.age > 24); // [{ id: 2, name: 'mike'}] -``` +```js +const data = [ + { + id: 1, + name: 'john', + age: 24 + }, + { + id: 2, + name: 'mike', + age: 50 + } +]; + +reducedFilter(data, ['id', 'name'], item => item.age > 24); // [{ id: 2, name: 'mike'}] +```

    [⬆ Back to top](#table-of-contents) -### remove - -Removes elements from an array for which the given function returns `false`. - -Use `Array.filter()` to find array elements that return truthy values and `Array.reduce()` to remove elements using `Array.splice()`. -The `func` is invoked with three arguments (`value, index, array`). - -```js -const remove = (arr, func) => - Array.isArray(arr) - ? arr.filter(func).reduce((acc, val) => { - arr.splice(arr.indexOf(val), 1); - return acc.concat(val); - }, []) - : []; -``` - +### remove + +Removes elements from an array for which the given function returns `false`. + +Use `Array.filter()` to find array elements that return truthy values and `Array.reduce()` to remove elements using `Array.splice()`. +The `func` is invoked with three arguments (`value, index, array`). + +```js +const remove = (arr, func) => + Array.isArray(arr) + ? arr.filter(func).reduce((acc, val) => { + arr.splice(arr.indexOf(val), 1); + return acc.concat(val); + }, []) + : []; +``` +
    Examples -```js -remove([1, 2, 3, 4], n => n % 2 == 0); // [2, 4] -``` +```js +remove([1, 2, 3, 4], n => n % 2 == 0); // [2, 4] +```

    [⬆ Back to top](#table-of-contents) -### sample - -Returns a random element from an array. - -Use `Math.random()` to generate a random number, multiply it by `length` and round it of to the nearest whole number using `Math.floor()`. -This method also works with strings. - -```js -const sample = arr => arr[Math.floor(Math.random() * arr.length)]; -``` - +### sample + +Returns a random element from an array. + +Use `Math.random()` to generate a random number, multiply it by `length` and round it of to the nearest whole number using `Math.floor()`. +This method also works with strings. + +```js +const sample = arr => arr[Math.floor(Math.random() * arr.length)]; +``` +
    Examples -```js -sample([3, 7, 9, 11]); // 9 -``` +```js +sample([3, 7, 9, 11]); // 9 +```

    [⬆ Back to top](#table-of-contents) -### sampleSize - -Gets `n` random elements at unique keys from `array` up to the size of `array`. - -Shuffle the array using the [Fisher-Yates algorithm](https://github.com/chalarangelo/30-seconds-of-code#shuffle). -Use `Array.slice()` to get the first `n` elements. -Omit the second argument, `n` to get only one element at random from the array. - -```js -const sampleSize = ([...arr], n = 1) => { - let m = arr.length; - while (m) { - const i = Math.floor(Math.random() * m--); - [arr[m], arr[i]] = [arr[i], arr[m]]; - } - return arr.slice(0, n); -}; -``` - +### sampleSize + +Gets `n` random elements at unique keys from `array` up to the size of `array`. + +Shuffle the array using the [Fisher-Yates algorithm](https://github.com/chalarangelo/30-seconds-of-code#shuffle). +Use `Array.slice()` to get the first `n` elements. +Omit the second argument, `n` to get only one element at random from the array. + +```js +const sampleSize = ([...arr], n = 1) => { + let m = arr.length; + while (m) { + const i = Math.floor(Math.random() * m--); + [arr[m], arr[i]] = [arr[i], arr[m]]; + } + return arr.slice(0, n); +}; +``` +
    Examples -```js -sampleSize([1, 2, 3], 2); // [3,1] -sampleSize([1, 2, 3], 4); // [2,3,1] -``` +```js +sampleSize([1, 2, 3], 2); // [3,1] +sampleSize([1, 2, 3], 4); // [2,3,1] +```

    [⬆ Back to top](#table-of-contents) -### shuffle - -Randomizes the order of the values of an array, returning a new array. - -Uses the [Fisher-Yates algorithm](https://github.com/chalarangelo/30-seconds-of-code#shuffle) to reorder the elements of the array. - -```js -const shuffle = ([...arr]) => { - let m = arr.length; - while (m) { - const i = Math.floor(Math.random() * m--); - [arr[m], arr[i]] = [arr[i], arr[m]]; - } - return arr; -}; -``` - +### shuffle + +Randomizes the order of the values of an array, returning a new array. + +Uses the [Fisher-Yates algorithm](https://github.com/chalarangelo/30-seconds-of-code#shuffle) to reorder the elements of the array. + +```js +const shuffle = ([...arr]) => { + let m = arr.length; + while (m) { + const i = Math.floor(Math.random() * m--); + [arr[m], arr[i]] = [arr[i], arr[m]]; + } + return arr; +}; +``` +
    Examples -```js -const foo = [1, 2, 3]; -shuffle(foo); // [2,3,1], foo = [1,2,3] -``` +```js +const foo = [1, 2, 3]; +shuffle(foo); // [2,3,1], foo = [1,2,3] +```

    [⬆ Back to top](#table-of-contents) -### similarity - -Returns an array of elements that appear in both arrays. - -Use `Array.filter()` to remove values that are not part of `values`, determined using `Array.includes()`. - -```js -const similarity = (arr, values) => arr.filter(v => values.includes(v)); -``` - +### similarity + +Returns an array of elements that appear in both arrays. + +Use `Array.filter()` to remove values that are not part of `values`, determined using `Array.includes()`. + +```js +const similarity = (arr, values) => arr.filter(v => values.includes(v)); +``` +
    Examples -```js -similarity([1, 2, 3], [1, 2, 4]); // [1,2] -``` +```js +similarity([1, 2, 3], [1, 2, 4]); // [1,2] +```

    [⬆ Back to top](#table-of-contents) -### sortedIndex - -Returns the lowest index at which value should be inserted into array in order to maintain its sort order. - -Check if the array is sorted in descending order (loosely). -Use `Array.findIndex()` to find the appropriate index where the element should be inserted. - -```js -const sortedIndex = (arr, n) => { - const isDescending = arr[0] > arr[arr.length - 1]; - const index = arr.findIndex(el => (isDescending ? n >= el : n <= el)); - return index === -1 ? arr.length : index; -}; -``` - +### sortedIndex + +Returns the lowest index at which value should be inserted into array in order to maintain its sort order. + +Check if the array is sorted in descending order (loosely). +Use `Array.findIndex()` to find the appropriate index where the element should be inserted. + +```js +const sortedIndex = (arr, n) => { + const isDescending = arr[0] > arr[arr.length - 1]; + const index = arr.findIndex(el => (isDescending ? n >= el : n <= el)); + return index === -1 ? arr.length : index; +}; +``` +
    Examples -```js -sortedIndex([5, 3, 2, 1], 4); // 1 -sortedIndex([30, 50], 40); // 1 -``` +```js +sortedIndex([5, 3, 2, 1], 4); // 1 +sortedIndex([30, 50], 40); // 1 +```

    [⬆ Back to top](#table-of-contents) -### symmetricDifference - -Returns the symmetric difference between two arrays. - -Create a `Set` from each array, then use `Array.filter()` on each of them to only keep values not contained in the other. - -```js -const symmetricDifference = (a, b) => { - const sA = new Set(a), - sB = new Set(b); - return [...a.filter(x => !sB.has(x)), ...b.filter(x => !sA.has(x))]; -}; -``` - +### symmetricDifference + +Returns the symmetric difference between two arrays. + +Create a `Set` from each array, then use `Array.filter()` on each of them to only keep values not contained in the other. + +```js +const symmetricDifference = (a, b) => { + const sA = new Set(a), + sB = new Set(b); + return [...a.filter(x => !sB.has(x)), ...b.filter(x => !sA.has(x))]; +}; +``` +
    Examples -```js -symmetricDifference([1, 2, 3], [1, 2, 4]); // [3,4] -``` +```js +symmetricDifference([1, 2, 3], [1, 2, 4]); // [3,4] +```

    [⬆ Back to top](#table-of-contents) -### tail - -Returns all elements in an array except for the first one. - -Return `Array.slice(1)` if the array's `length` is more than `1`, otherwise, return the whole array. - -```js -const tail = arr => (arr.length > 1 ? arr.slice(1) : arr); -``` - +### tail + +Returns all elements in an array except for the first one. + +Return `Array.slice(1)` if the array's `length` is more than `1`, otherwise, return the whole array. + +```js +const tail = arr => (arr.length > 1 ? arr.slice(1) : arr); +``` +
    Examples -```js -tail([1, 2, 3]); // [2,3] -tail([1]); // [1] -``` +```js +tail([1, 2, 3]); // [2,3] +tail([1]); // [1] +```

    [⬆ Back to top](#table-of-contents) -### take - -Returns an array with n elements removed from the beginning. - -Use `Array.slice()` to create a slice of the array with `n` elements taken from the beginning. - -```js -const take = (arr, n = 1) => arr.slice(0, n); -``` - +### take + +Returns an array with n elements removed from the beginning. + +Use `Array.slice()` to create a slice of the array with `n` elements taken from the beginning. + +```js +const take = (arr, n = 1) => arr.slice(0, n); +``` +
    Examples -```js -take([1, 2, 3], 5); // [1, 2, 3] -take([1, 2, 3], 0); // [] -``` +```js +take([1, 2, 3], 5); // [1, 2, 3] +take([1, 2, 3], 0); // [] +```

    [⬆ Back to top](#table-of-contents) -### takeRight - -Returns an array with n elements removed from the end. - -Use `Array.slice()` to create a slice of the array with `n` elements taken from the end. - -```js -const takeRight = (arr, n = 1) => arr.slice(arr.length - n, arr.length); -``` - +### takeRight + +Returns an array with n elements removed from the end. + +Use `Array.slice()` to create a slice of the array with `n` elements taken from the end. + +```js +const takeRight = (arr, n = 1) => arr.slice(arr.length - n, arr.length); +``` +
    Examples -```js -takeRight([1, 2, 3], 2); // [ 2, 3 ] -takeRight([1, 2, 3]); // [3] -``` +```js +takeRight([1, 2, 3], 2); // [ 2, 3 ] +takeRight([1, 2, 3]); // [3] +```

    [⬆ Back to top](#table-of-contents) -### union - -Returns every element that exists in any of the two arrays once. - -Create a `Set` with all values of `a` and `b` and convert to an array. - -```js -const union = (a, b) => Array.from(new Set([...a, ...b])); -``` - +### union + +Returns every element that exists in any of the two arrays once. + +Create a `Set` with all values of `a` and `b` and convert to an array. + +```js +const union = (a, b) => Array.from(new Set([...a, ...b])); +``` +
    Examples -```js -union([1, 2, 3], [4, 3, 2]); // [1,2,3,4] -``` +```js +union([1, 2, 3], [4, 3, 2]); // [1,2,3,4] +```

    [⬆ Back to top](#table-of-contents) -### without - -Filters out the elements of an array, that have one of the specified values. - -Use `Array.filter()` to create an array excluding(using `!Array.includes()`) all given values. - -_(For a snippet that mutates the original array see [`pull`](#pull))_ - -```js -const without = (arr, ...args) => arr.filter(v => !args.includes(v)); -``` - +### without + +Filters out the elements of an array, that have one of the specified values. + +Use `Array.filter()` to create an array excluding(using `!Array.includes()`) all given values. + +_(For a snippet that mutates the original array see [`pull`](#pull))_ + +```js +const without = (arr, ...args) => arr.filter(v => !args.includes(v)); +``` +
    Examples -```js -without([2, 1, 2, 3], 1, 2); // [3] -``` +```js +without([2, 1, 2, 3], 1, 2); // [3] +```

    [⬆ Back to top](#table-of-contents) -### zip - -Creates an array of elements, grouped based on the position in the original arrays. - -Use `Math.max.apply()` to get the longest array in the arguments. -Creates an array with that length as return value and use `Array.from()` with a map-function to create an array of grouped elements. -If lengths of the argument-arrays vary, `undefined` is used where no value could be found. - -```js -const zip = (...arrays) => { - const maxLength = Math.max(...arrays.map(x => x.length)); - return Array.from({ length: maxLength }).map((_, i) => { - return Array.from({ length: arrays.length }, (_, k) => arrays[k][i]); - }); -}; -``` - +### zip + +Creates an array of elements, grouped based on the position in the original arrays. + +Use `Math.max.apply()` to get the longest array in the arguments. +Creates an array with that length as return value and use `Array.from()` with a map-function to create an array of grouped elements. +If lengths of the argument-arrays vary, `undefined` is used where no value could be found. + +```js +const zip = (...arrays) => { + const maxLength = Math.max(...arrays.map(x => x.length)); + return Array.from({ length: maxLength }).map((_, i) => { + return Array.from({ length: arrays.length }, (_, k) => arrays[k][i]); + }); +}; +``` +
    Examples -```js -zip(['a', 'b'], [1, 2], [true, false]); // [['a', 1, true], ['b', 2, false]] -zip(['a'], [1, 2], [true, false]); // [['a', 1, true], [undefined, 2, false]] -``` +```js +zip(['a', 'b'], [1, 2], [true, false]); // [['a', 1, true], ['b', 2, false]] +zip(['a'], [1, 2], [true, false]); // [['a', 1, true], [undefined, 2, false]] +```

    [⬆ Back to top](#table-of-contents) -### zipObject - -Given an array of valid property identifiers and an array of values, return an object associating the properties to the values. - -Since an object can have undefined values but not undefined property pointers, the array of properties is used to decide the structure of the resulting object using `Array.reduce()`. - -```js -const zipObject = (props, values) => - props.reduce((obj, prop, index) => ((obj[prop] = values[index]), obj), {}); -``` - +### zipObject + +Given an array of valid property identifiers and an array of values, return an object associating the properties to the values. + +Since an object can have undefined values but not undefined property pointers, the array of properties is used to decide the structure of the resulting object using `Array.reduce()`. + +```js +const zipObject = (props, values) => + props.reduce((obj, prop, index) => ((obj[prop] = values[index]), obj), {}); +``` +
    Examples -```js -zipObject(['a', 'b', 'c'], [1, 2]); // {a: 1, b: 2, c: undefined} -zipObject(['a', 'b'], [1, 2, 3]); // {a: 1, b: 2} -``` +```js +zipObject(['a', 'b', 'c'], [1, 2]); // {a: 1, b: 2, c: undefined} +zipObject(['a', 'b'], [1, 2, 3]); // {a: 1, b: 2} +```
    @@ -1726,47 +1726,47 @@ zipObject(['a', 'b'], [1, 2, 3]); // {a: 1, b: 2} --- ## 🌐 Browser -### arrayToHtmlList - -Converts the given array elements into `
  • ` tags and appends them to the list of the given id. - -Use `Array.map()` and `document.querySelector()` to create a list of html tags. - -```js -const arrayToHtmlList = (arr, listID) => - arr.map(item => (document.querySelector('#' + listID).innerHTML += `
  • ${item}
    • `)); -``` - +### arrayToHtmlList + +Converts the given array elements into `
  • ` tags and appends them to the list of the given id. + +Use `Array.map()` and `document.querySelector()` to create a list of html tags. + +```js +const arrayToHtmlList = (arr, listID) => + arr.map(item => (document.querySelector('#' + listID).innerHTML += `
  • ${item}
    • `)); +``` +
    Examples -```js -arrayToHtmlList(['item 1', 'item 2'], 'myListID'); -``` +```js +arrayToHtmlList(['item 1', 'item 2'], 'myListID'); +```

    [⬆ Back to top](#table-of-contents) -### bottomVisible - -Returns `true` if the bottom of the page is visible, `false` otherwise. - -Use `scrollY`, `scrollHeight` and `clientHeight` to determine if the bottom of the page is visible. - -```js -const bottomVisible = () => - document.documentElement.clientHeight + window.scrollY >= - (document.documentElement.scrollHeight || document.documentElement.clientHeight); -``` - +### bottomVisible + +Returns `true` if the bottom of the page is visible, `false` otherwise. + +Use `scrollY`, `scrollHeight` and `clientHeight` to determine if the bottom of the page is visible. + +```js +const bottomVisible = () => + document.documentElement.clientHeight + window.scrollY >= + (document.documentElement.scrollHeight || document.documentElement.clientHeight); +``` +
    Examples -```js -bottomVisible(); // true -``` +```js +bottomVisible(); // true +```
    @@ -1815,287 +1815,287 @@ copyToClipboard('Lorem ipsum'); // 'Lorem ipsum' copied to clipboard.
    [⬆ Back to top](#table-of-contents) -### createElement - -Creates an element from a string (without appending it to the document). -If the given string contains multiple elements, only the first one will be returned. - -Use `document.createElement()` to create a new element. -Set its `innerHTML` to the string supplied as the argument. -Use `ParentNode.firstElementChild` to return the element version of the string. - -```js -const createElement = str => { - const el = document.createElement('div'); - el.innerHTML = str; - return el.firstElementChild; -}; -``` - +### createElement + +Creates an element from a string (without appending it to the document). +If the given string contains multiple elements, only the first one will be returned. + +Use `document.createElement()` to create a new element. +Set its `innerHTML` to the string supplied as the argument. +Use `ParentNode.firstElementChild` to return the element version of the string. + +```js +const createElement = str => { + const el = document.createElement('div'); + el.innerHTML = str; + return el.firstElementChild; +}; +``` +
    Examples -```js -const el = createElement( - `
    -

    Hello!

    -
    ` -); -console.log(el.className); // 'container' -``` +```js +const el = createElement( + `
    +

    Hello!

    +
    ` +); +console.log(el.className); // 'container' +```

    [⬆ Back to top](#table-of-contents) -### currentURL - -Returns the current URL. - -Use `window.location.href` to get current URL. - -```js -const currentURL = () => window.location.href; -``` - +### currentURL + +Returns the current URL. + +Use `window.location.href` to get current URL. + +```js +const currentURL = () => window.location.href; +``` +
    Examples -```js -currentURL(); // 'https://google.com' -``` +```js +currentURL(); // 'https://google.com' +```

    [⬆ Back to top](#table-of-contents) -### detectDeviceType - -Detects wether the website is being opened in a mobile device or a desktop/laptop. - -Use a regular expression to test the `navigator.userAgent` property to figure out if the device is a mobile device or a desktop/laptop. - -```js -const detectDeviceType = () => - /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) - ? 'Mobile' - : 'Desktop'; -``` - +### detectDeviceType + +Detects wether the website is being opened in a mobile device or a desktop/laptop. + +Use a regular expression to test the `navigator.userAgent` property to figure out if the device is a mobile device or a desktop/laptop. + +```js +const detectDeviceType = () => + /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) + ? 'Mobile' + : 'Desktop'; +``` +
    Examples -```js -detectDeviceType(); // "Mobile" or "Desktop" -``` +```js +detectDeviceType(); // "Mobile" or "Desktop" +```

    [⬆ Back to top](#table-of-contents) -### elementIsVisibleInViewport - -Returns `true` if the element specified is visible in the viewport, `false` otherwise. - -Use `Element.getBoundingClientRect()` and the `window.inner(Width|Height)` values -to determine if a given element is visible in the viewport. -Omit the second argument to determine if the element is entirely visible, or specify `true` to determine if -it is partially visible. - -```js -const elementIsVisibleInViewport = (el, partiallyVisible = false) => { - const { top, left, bottom, right } = el.getBoundingClientRect(); - const { innerHeight, innerWidth } = window; - return partiallyVisible - ? ((top > 0 && top < innerHeight) || (bottom > 0 && bottom < innerHeight)) && - ((left > 0 && left < innerWidth) || (right > 0 && right < innerWidth)) - : top >= 0 && left >= 0 && bottom <= innerHeight && right <= innerWidth; -}; -``` - +### elementIsVisibleInViewport + +Returns `true` if the element specified is visible in the viewport, `false` otherwise. + +Use `Element.getBoundingClientRect()` and the `window.inner(Width|Height)` values +to determine if a given element is visible in the viewport. +Omit the second argument to determine if the element is entirely visible, or specify `true` to determine if +it is partially visible. + +```js +const elementIsVisibleInViewport = (el, partiallyVisible = false) => { + const { top, left, bottom, right } = el.getBoundingClientRect(); + const { innerHeight, innerWidth } = window; + return partiallyVisible + ? ((top > 0 && top < innerHeight) || (bottom > 0 && bottom < innerHeight)) && + ((left > 0 && left < innerWidth) || (right > 0 && right < innerWidth)) + : top >= 0 && left >= 0 && bottom <= innerHeight && right <= innerWidth; +}; +``` +
    Examples -```js -// e.g. 100x100 viewport and a 10x10px element at position {top: -1, left: 0, bottom: 9, right: 10} -elementIsVisibleInViewport(el); // false - (not fully visible) -elementIsVisibleInViewport(el, true); // true - (partially visible) -``` +```js +// e.g. 100x100 viewport and a 10x10px element at position {top: -1, left: 0, bottom: 9, right: 10} +elementIsVisibleInViewport(el); // false - (not fully visible) +elementIsVisibleInViewport(el, true); // true - (partially visible) +```

    [⬆ Back to top](#table-of-contents) -### getScrollPosition - -Returns the scroll position of the current page. - -Use `pageXOffset` and `pageYOffset` if they are defined, otherwise `scrollLeft` and `scrollTop`. -You can omit `el` to use a default value of `window`. - -```js -const getScrollPosition = (el = window) => ({ - x: el.pageXOffset !== undefined ? el.pageXOffset : el.scrollLeft, - y: el.pageYOffset !== undefined ? el.pageYOffset : el.scrollTop -}); -``` - +### getScrollPosition + +Returns the scroll position of the current page. + +Use `pageXOffset` and `pageYOffset` if they are defined, otherwise `scrollLeft` and `scrollTop`. +You can omit `el` to use a default value of `window`. + +```js +const getScrollPosition = (el = window) => ({ + x: el.pageXOffset !== undefined ? el.pageXOffset : el.scrollLeft, + y: el.pageYOffset !== undefined ? el.pageYOffset : el.scrollTop +}); +``` +
    Examples -```js -getScrollPosition(); // {x: 0, y: 200} -``` +```js +getScrollPosition(); // {x: 0, y: 200} +```

    [⬆ Back to top](#table-of-contents) -### getStyle - -Returns the value of a CSS rule for the specified element. - -Use `Window.getComputedStyle()` to get the value of the CSS rule for the specified element. - -```js -const getStyle = (el, ruleName) => getComputedStyle(el)[ruleName]; -``` - +### getStyle + +Returns the value of a CSS rule for the specified element. + +Use `Window.getComputedStyle()` to get the value of the CSS rule for the specified element. + +```js +const getStyle = (el, ruleName) => getComputedStyle(el)[ruleName]; +``` +
    Examples -```js -getStyle(document.querySelector('p'), 'font-size'); // '16px' -``` +```js +getStyle(document.querySelector('p'), 'font-size'); // '16px' +```

    [⬆ Back to top](#table-of-contents) -### hasClass - -Returns `true` if the element has the specified class, `false` otherwise. - -Use `element.classList.contains()` to check if the element has the specified class. - -```js -const hasClass = (el, className) => el.classList.contains(className); -``` - +### hasClass + +Returns `true` if the element has the specified class, `false` otherwise. + +Use `element.classList.contains()` to check if the element has the specified class. + +```js +const hasClass = (el, className) => el.classList.contains(className); +``` +
    Examples -```js -hasClass(document.querySelector('p.special'), 'special'); // true -``` +```js +hasClass(document.querySelector('p.special'), 'special'); // true +```

    [⬆ Back to top](#table-of-contents) -### hide - -Hides all the elements specified. - -Use the spread operator (`...`) and `Array.forEach()` to apply `display: none` to each element specified. - -```js -const hide = (...el) => [...el].forEach(e => (e.style.display = 'none')); -``` - +### hide + +Hides all the elements specified. + +Use the spread operator (`...`) and `Array.forEach()` to apply `display: none` to each element specified. + +```js +const hide = (...el) => [...el].forEach(e => (e.style.display = 'none')); +``` +
    Examples -```js -hide(document.querySelectorAll('img')); // Hides all elements on the page -``` +```js +hide(document.querySelectorAll('img')); // Hides all elements on the page +```

    [⬆ Back to top](#table-of-contents) -### httpsRedirect - -Redirects the page to HTTPS if its currently in HTTP. Also, pressing the back button doesn't take it back to the HTTP page as its replaced in the history. - -Use `location.protocol` to get the protocol currently being used. If it's not HTTPS, use `location.replace()` to replace the existing page with the HTTPS version of the page. Use `location.href` to get the full address, split it with `String.split()` and remove the protocol part of the URL. - -```js -const httpsRedirect = () => { - if (location.protocol !== 'https:') location.replace('https://' + location.href.split('//')[1]); -}; -``` - +### httpsRedirect + +Redirects the page to HTTPS if its currently in HTTP. Also, pressing the back button doesn't take it back to the HTTP page as its replaced in the history. + +Use `location.protocol` to get the protocol currently being used. If it's not HTTPS, use `location.replace()` to replace the existing page with the HTTPS version of the page. Use `location.href` to get the full address, split it with `String.split()` and remove the protocol part of the URL. + +```js +const httpsRedirect = () => { + if (location.protocol !== 'https:') location.replace('https://' + location.href.split('//')[1]); +}; +``` +
    Examples -```js -httpsRedirect(); // If you are on http://mydomain.com, you are redirected to https://mydomain.com -``` +```js +httpsRedirect(); // If you are on http://mydomain.com, you are redirected to https://mydomain.com +```

    [⬆ Back to top](#table-of-contents) -### off - -Removes an event listener from an element. - -Use `EventTarget.removeEventListener()` to remove an event listener from an element. -Omit the fourth argument `opts` to use `false` or specify it based on the options used when the event listener was added. - -```js -const off = (el, evt, fn, opts = false) => el.removeEventListener(evt, fn, opts); -``` - +### off + +Removes an event listener from an element. + +Use `EventTarget.removeEventListener()` to remove an event listener from an element. +Omit the fourth argument `opts` to use `false` or specify it based on the options used when the event listener was added. + +```js +const off = (el, evt, fn, opts = false) => el.removeEventListener(evt, fn, opts); +``` +
    Examples -```js -const fn = () => console.log('!'); -document.body.addEventListener('click', fn); -off(document.body, 'click', fn); // no longer logs '!' upon clicking on the page -``` +```js +const fn = () => console.log('!'); +document.body.addEventListener('click', fn); +off(document.body, 'click', fn); // no longer logs '!' upon clicking on the page +```

    [⬆ Back to top](#table-of-contents) -### on - -Adds an event listener to an element with the ability to use event delegation. - -Use `EventTarget.addEventListener()` to add an event listener to an element. If there is a `target` property supplied to the options object, ensure the event target matches the target specified and then invoke the callback by supplying the correct `this` context. -Returns a reference to the custom delegator function, in order to be possible to use with [`off`](#off). -Omit `opts` to default to non-delegation behavior and event bubbling. - -```js -const on = (el, evt, fn, opts = {}) => { - const delegatorFn = e => e.target.matches(opts.target) && fn.call(e.target, e); - el.addEventListener(evt, opts.target ? delegatorFn : fn, opts.options || false); - if (opts.target) return delegatorFn; -}; -``` - +### on + +Adds an event listener to an element with the ability to use event delegation. + +Use `EventTarget.addEventListener()` to add an event listener to an element. If there is a `target` property supplied to the options object, ensure the event target matches the target specified and then invoke the callback by supplying the correct `this` context. +Returns a reference to the custom delegator function, in order to be possible to use with [`off`](#off). +Omit `opts` to default to non-delegation behavior and event bubbling. + +```js +const on = (el, evt, fn, opts = {}) => { + const delegatorFn = e => e.target.matches(opts.target) && fn.call(e.target, e); + el.addEventListener(evt, opts.target ? delegatorFn : fn, opts.options || false); + if (opts.target) return delegatorFn; +}; +``` +
    Examples -```js -const fn = () => console.log('!'); -on(document.body, 'click', fn); // logs '!' upon clicking the body -on(document.body, 'click', fn, { target: 'p' }); // logs '!' upon clicking a `p` element child of the body -on(document.body, 'click', fn, { options: true }); // use capturing instead of bubbling -``` +```js +const fn = () => console.log('!'); +on(document.body, 'click', fn); // logs '!' upon clicking the body +on(document.body, 'click', fn, { target: 'p' }); // logs '!' upon clicking a `p` element child of the body +on(document.body, 'click', fn, { options: true }); // use capturing instead of bubbling +```
    @@ -2141,24 +2141,24 @@ onUserInputChange(type => {
    [⬆ Back to top](#table-of-contents) -### redirect - -Redirects to a specified URL. - -Use `window.location.href` or `window.location.replace()` to redirect to `url`. -Pass a second argument to simulate a link click (`true` - default) or an HTTP redirect (`false`). - -```js -const redirect = (url, asLink = true) => - asLink ? (window.location.href = url) : window.location.replace(url); -``` - +### redirect + +Redirects to a specified URL. + +Use `window.location.href` or `window.location.replace()` to redirect to `url`. +Pass a second argument to simulate a link click (`true` - default) or an HTTP redirect (`false`). + +```js +const redirect = (url, asLink = true) => + asLink ? (window.location.href = url) : window.location.replace(url); +``` +
    Examples -```js -redirect('https://google.com'); -``` +```js +redirect('https://google.com'); +```
    @@ -2223,120 +2223,120 @@ runAsync(() => typeof outsideVariable).then(console.log); // 'undefined'
    [⬆ Back to top](#table-of-contents) -### scrollToTop - -Smooth-scrolls to the top of the page. - -Get distance from top using `document.documentElement.scrollTop` or `document.body.scrollTop`. -Scroll by a fraction of the distance from the top. Use `window.requestAnimationFrame()` to animate the scrolling. - -```js -const scrollToTop = () => { - const c = document.documentElement.scrollTop || document.body.scrollTop; - if (c > 0) { - window.requestAnimationFrame(scrollToTop); - window.scrollTo(0, c - c / 8); - } -}; -``` - +### scrollToTop + +Smooth-scrolls to the top of the page. + +Get distance from top using `document.documentElement.scrollTop` or `document.body.scrollTop`. +Scroll by a fraction of the distance from the top. Use `window.requestAnimationFrame()` to animate the scrolling. + +```js +const scrollToTop = () => { + const c = document.documentElement.scrollTop || document.body.scrollTop; + if (c > 0) { + window.requestAnimationFrame(scrollToTop); + window.scrollTo(0, c - c / 8); + } +}; +``` +
    Examples -```js -scrollToTop(); -``` +```js +scrollToTop(); +```

    [⬆ Back to top](#table-of-contents) -### setStyle - -Sets the value of a CSS rule for the specified element. - -Use `element.style` to set the value of the CSS rule for the specified element to `val`. - -```js -const setStyle = (el, ruleName, val) => (el.style[ruleName] = val); -``` - +### setStyle + +Sets the value of a CSS rule for the specified element. + +Use `element.style` to set the value of the CSS rule for the specified element to `val`. + +```js +const setStyle = (el, ruleName, val) => (el.style[ruleName] = val); +``` +
    Examples -```js -setStyle(document.querySelector('p'), 'font-size', '20px'); // The first

    element on the page will have a font-size of 20px -``` +```js +setStyle(document.querySelector('p'), 'font-size', '20px'); // The first

    element on the page will have a font-size of 20px +```


    [⬆ Back to top](#table-of-contents) -### show - -Shows all the elements specified. - -Use the spread operator (`...`) and `Array.forEach()` to clear the `display` property for each element specified. - -```js -const show = (...el) => [...el].forEach(e => (e.style.display = '')); -``` - +### show + +Shows all the elements specified. + +Use the spread operator (`...`) and `Array.forEach()` to clear the `display` property for each element specified. + +```js +const show = (...el) => [...el].forEach(e => (e.style.display = '')); +``` +
    Examples -```js -show(document.querySelectorAll('img')); // Shows all elements on the page -``` +```js +show(document.querySelectorAll('img')); // Shows all elements on the page +```

    [⬆ Back to top](#table-of-contents) -### toggleClass - -Toggle a class for an element. - -Use `element.classList.toggle()` to toggle the specified class for the element. - -```js -const toggleClass = (el, className) => el.classList.toggle(className); -``` - +### toggleClass + +Toggle a class for an element. + +Use `element.classList.toggle()` to toggle the specified class for the element. + +```js +const toggleClass = (el, className) => el.classList.toggle(className); +``` +
    Examples -```js -toggleClass(document.querySelector('p.special'), 'special'); // The paragraph will not have the 'special' class anymore -``` +```js +toggleClass(document.querySelector('p.special'), 'special'); // The paragraph will not have the 'special' class anymore +```

    [⬆ Back to top](#table-of-contents) -### UUIDGeneratorBrowser - -Generates a UUID in a browser. - -Use `crypto` API to generate a UUID, compliant with [RFC4122](https://www.ietf.org/rfc/rfc4122.txt) version 4. - -```js -const UUIDGeneratorBrowser = () => - ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c => - (c ^ (crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (c / 4)))).toString(16) - ); -``` - +### UUIDGeneratorBrowser + +Generates a UUID in a browser. + +Use `crypto` API to generate a UUID, compliant with [RFC4122](https://www.ietf.org/rfc/rfc4122.txt) version 4. + +```js +const UUIDGeneratorBrowser = () => + ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c => + (c ^ (crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (c / 4)))).toString(16) + ); +``` +
    Examples -```js -UUIDGeneratorBrowser(); // '7982fcfe-5721-4632-bede-6000885be57d' -``` +```js +UUIDGeneratorBrowser(); // '7982fcfe-5721-4632-bede-6000885be57d' +```
    @@ -2345,113 +2345,113 @@ UUIDGeneratorBrowser(); // '7982fcfe-5721-4632-bede-6000885be57d' --- ## ⏱️ Date -### formatDuration - -Returns the human readable format of the given number of milliseconds. - -Divide `ms` with the appropriate values to obtain the appropriate values for `day`, `hour`, `minute`, `second` and `millisecond`. -Use `Object.entries()` with `Array.filter()` to keep only non-zero values. -Use `Array.map()` to create the string for each value, pluralizing appropriately. -Use `String.join(', ')` to combine the values into a string. - -```js -const formatDuration = ms => { - if (ms < 0) ms = -ms; - const time = { - day: Math.floor(ms / 86400000), - hour: Math.floor(ms / 3600000) % 24, - minute: Math.floor(ms / 60000) % 60, - second: Math.floor(ms / 1000) % 60, - millisecond: Math.floor(ms) % 1000 - }; - return Object.entries(time) - .filter(val => val[1] !== 0) - .map(val => val[1] + ' ' + (val[1] !== 1 ? val[0] + 's' : val[0])) - .join(', '); -}; -``` - +### formatDuration + +Returns the human readable format of the given number of milliseconds. + +Divide `ms` with the appropriate values to obtain the appropriate values for `day`, `hour`, `minute`, `second` and `millisecond`. +Use `Object.entries()` with `Array.filter()` to keep only non-zero values. +Use `Array.map()` to create the string for each value, pluralizing appropriately. +Use `String.join(', ')` to combine the values into a string. + +```js +const formatDuration = ms => { + if (ms < 0) ms = -ms; + const time = { + day: Math.floor(ms / 86400000), + hour: Math.floor(ms / 3600000) % 24, + minute: Math.floor(ms / 60000) % 60, + second: Math.floor(ms / 1000) % 60, + millisecond: Math.floor(ms) % 1000 + }; + return Object.entries(time) + .filter(val => val[1] !== 0) + .map(val => val[1] + ' ' + (val[1] !== 1 ? val[0] + 's' : val[0])) + .join(', '); +}; +``` +
    Examples -```js -formatDuration(1001); // '1 second, 1 millisecond' -formatDuration(34325055574); // '397 days, 6 hours, 44 minutes, 15 seconds, 574 milliseconds' -``` +```js +formatDuration(1001); // '1 second, 1 millisecond' +formatDuration(34325055574); // '397 days, 6 hours, 44 minutes, 15 seconds, 574 milliseconds' +```

    [⬆ Back to top](#table-of-contents) -### getDaysDiffBetweenDates - -Returns the difference (in days) between two dates. - -Calculate the difference (in days) between two `Date` objects. - -```js -const getDaysDiffBetweenDates = (dateInitial, dateFinal) => - (dateFinal - dateInitial) / (1000 * 3600 * 24); -``` - +### getDaysDiffBetweenDates + +Returns the difference (in days) between two dates. + +Calculate the difference (in days) between two `Date` objects. + +```js +const getDaysDiffBetweenDates = (dateInitial, dateFinal) => + (dateFinal - dateInitial) / (1000 * 3600 * 24); +``` +
    Examples -```js -getDaysDiffBetweenDates(new Date('2017-12-13'), new Date('2017-12-22')); // 9 -``` +```js +getDaysDiffBetweenDates(new Date('2017-12-13'), new Date('2017-12-22')); // 9 +```

    [⬆ Back to top](#table-of-contents) -### toEnglishDate - -Converts a date from American format to English format. - -Use `Date.toISOString()`, `split('T')` and `replace()` to convert a date from American format to the English format. -Throws an error if the passed time cannot be converted to a date. - -```js -const toEnglishDate = time => { - try { - return new Date(time) - .toISOString() - .split('T')[0] - .replace(/-/g, '/'); - } catch (e) {} -}; -``` - +### toEnglishDate + +Converts a date from American format to English format. + +Use `Date.toISOString()`, `split('T')` and `replace()` to convert a date from American format to the English format. +Throws an error if the passed time cannot be converted to a date. + +```js +const toEnglishDate = time => { + try { + return new Date(time) + .toISOString() + .split('T')[0] + .replace(/-/g, '/'); + } catch (e) {} +}; +``` +
    Examples -```js -toEnglishDate('09/21/2010'); // '21/09/2010' -``` +```js +toEnglishDate('09/21/2010'); // '21/09/2010' +```

    [⬆ Back to top](#table-of-contents) -### tomorrow - -Results in a string representation of tomorrow's date. -Use `new Date()` to get today's date, adding `86400000` of seconds to it(24 hours), using `Date.toISOString()` to convert Date object to string. - -```js -const tomorrow = () => new Date(new Date().getTime() + 86400000).toISOString().split('T')[0]; -``` - +### tomorrow + +Results in a string representation of tomorrow's date. +Use `new Date()` to get today's date, adding `86400000` of seconds to it(24 hours), using `Date.toISOString()` to convert Date object to string. + +```js +const tomorrow = () => new Date(new Date().getTime() + 86400000).toISOString().split('T')[0]; +``` +
    Examples -```js -tomorrow(); // 2017-12-27 (if current date is 2017-12-26) -``` +```js +tomorrow(); // 2017-12-27 (if current date is 2017-12-26) +```
    @@ -2460,254 +2460,254 @@ tomorrow(); // 2017-12-27 (if current date is 2017-12-26) --- ## 🎛️ Function -### chainAsync - -Chains asynchronous functions. - -Loop through an array of functions containing asynchronous events, calling `next` when each asynchronous event has completed. - -```js -const chainAsync = fns => { - let curr = 0; - const next = () => fns[curr++](next); - next(); -}; -``` - +### chainAsync + +Chains asynchronous functions. + +Loop through an array of functions containing asynchronous events, calling `next` when each asynchronous event has completed. + +```js +const chainAsync = fns => { + let curr = 0; + const next = () => fns[curr++](next); + next(); +}; +``` +
    Examples -```js -chainAsync([ - next => { - console.log('0 seconds'); - setTimeout(next, 1000); - }, - next => { - console.log('1 second'); - } -]); -``` +```js +chainAsync([ + next => { + console.log('0 seconds'); + setTimeout(next, 1000); + }, + next => { + console.log('1 second'); + } +]); +```

    [⬆ Back to top](#table-of-contents) -### compose - -Performs right-to-left function composition. - -Use `Array.reduce()` to perform right-to-left function composition. -The last (rightmost) function can accept one or more arguments; the remaining functions must be unary. - -```js -const compose = (...fns) => fns.reduce((f, g) => (...args) => f(g(...args))); -``` - +### compose + +Performs right-to-left function composition. + +Use `Array.reduce()` to perform right-to-left function composition. +The last (rightmost) function can accept one or more arguments; the remaining functions must be unary. + +```js +const compose = (...fns) => fns.reduce((f, g) => (...args) => f(g(...args))); +``` +
    Examples -```js -const add5 = x => x + 5; -const multiply = (x, y) => x * y; -const multiplyAndAdd5 = compose(add5, multiply); -multiplyAndAdd5(5, 2); // 15 -``` +```js +const add5 = x => x + 5; +const multiply = (x, y) => x * y; +const multiplyAndAdd5 = compose(add5, multiply); +multiplyAndAdd5(5, 2); // 15 +```

    [⬆ Back to top](#table-of-contents) -### curry - -Curries a function. - -Use recursion. -If the number of provided arguments (`args`) is sufficient, call the passed function `fn`. -Otherwise, return a curried function `fn` that expects the rest of the arguments. -If you want to curry a function that accepts a variable number of arguments (a variadic function, e.g. `Math.min()`), you can optionally pass the number of arguments to the second parameter `arity`. - -```js -const curry = (fn, arity = fn.length, ...args) => - arity <= args.length ? fn(...args) : curry.bind(null, fn, arity, ...args); -``` - +### curry + +Curries a function. + +Use recursion. +If the number of provided arguments (`args`) is sufficient, call the passed function `fn`. +Otherwise, return a curried function `fn` that expects the rest of the arguments. +If you want to curry a function that accepts a variable number of arguments (a variadic function, e.g. `Math.min()`), you can optionally pass the number of arguments to the second parameter `arity`. + +```js +const curry = (fn, arity = fn.length, ...args) => + arity <= args.length ? fn(...args) : curry.bind(null, fn, arity, ...args); +``` +
    Examples -```js -curry(Math.pow)(2)(10); // 1024 -curry(Math.min, 3)(10)(50)(2); // 2 -``` +```js +curry(Math.pow)(2)(10); // 1024 +curry(Math.min, 3)(10)(50)(2); // 2 +```

    [⬆ Back to top](#table-of-contents) -### defer - -Defers invoking a function until the current call stack has cleared. - -Use `setTimeout()` with a timeout of 1ms to add a new event to the browser event queue and allow the rendering engine to complete its work. Use the spread (`...`) operator to supply the function with an arbitrary number of arguments. - -```js -const defer = (fn, ...args) => setTimeout(fn, 1, ...args); -``` - +### defer + +Defers invoking a function until the current call stack has cleared. + +Use `setTimeout()` with a timeout of 1ms to add a new event to the browser event queue and allow the rendering engine to complete its work. Use the spread (`...`) operator to supply the function with an arbitrary number of arguments. + +```js +const defer = (fn, ...args) => setTimeout(fn, 1, ...args); +``` +
    Examples -```js -// Example A: -defer(console.log, 'a'), console.log('b'); // logs 'b' then 'a' - -// Example B: -document.querySelector('#someElement').innerHTML = 'Hello'; -longRunningFunction(); //Browser will not update the HTML until this has finished -defer(longRunningFunction); // Browser will update the HTML then run the function -``` +```js +// Example A: +defer(console.log, 'a'), console.log('b'); // logs 'b' then 'a' + +// Example B: +document.querySelector('#someElement').innerHTML = 'Hello'; +longRunningFunction(); //Browser will not update the HTML until this has finished +defer(longRunningFunction); // Browser will update the HTML then run the function +```

    [⬆ Back to top](#table-of-contents) -### functionName - -Logs the name of a function. - -Use `console.debug()` and the `name` property of the passed method to log the method's name to the `debug` channel of the console. - -```js -const functionName = fn => (console.debug(fn.name), fn); -``` - +### functionName + +Logs the name of a function. + +Use `console.debug()` and the `name` property of the passed method to log the method's name to the `debug` channel of the console. + +```js +const functionName = fn => (console.debug(fn.name), fn); +``` +
    Examples -```js -functionName(Math.max); // max (logged in debug channel of console) -``` +```js +functionName(Math.max); // max (logged in debug channel of console) +```

    [⬆ Back to top](#table-of-contents) -### memoize - -Returns the memoized (cached) function. - -Create an empty cache by instantiating a new `Map` object. -Return a function which takes a single argument to be supplied to the memoized function by first checking if the function's output for that specific input value is already cached, or store and return it if not. The `function` keyword must be used in order to allow the memoized function to have its `this` context changed if necessary. -Allow access to the `cache` by setting it as a property on the returned function. - -```js -const memoize = fn => { - const cache = new Map(); - const cached = function(val) { - return cache.has(val) ? cache.get(val) : cache.set(val, fn.call(this, val)) && cache.get(val); - }; - cached.cache = cache; - return cached; -}; -``` - +### memoize + +Returns the memoized (cached) function. + +Create an empty cache by instantiating a new `Map` object. +Return a function which takes a single argument to be supplied to the memoized function by first checking if the function's output for that specific input value is already cached, or store and return it if not. The `function` keyword must be used in order to allow the memoized function to have its `this` context changed if necessary. +Allow access to the `cache` by setting it as a property on the returned function. + +```js +const memoize = fn => { + const cache = new Map(); + const cached = function(val) { + return cache.has(val) ? cache.get(val) : cache.set(val, fn.call(this, val)) && cache.get(val); + }; + cached.cache = cache; + return cached; +}; +``` +
    Examples -```js -// See the `anagrams` snippet. -const anagramsCached = memoize(anagrams); -anagramsCached('javascript'); // takes a long time -anagramsCached('javascript'); // returns virtually instantly since it's now cached -console.log(anagramsCached.cache); // The cached anagrams map -``` +```js +// See the `anagrams` snippet. +const anagramsCached = memoize(anagrams); +anagramsCached('javascript'); // takes a long time +anagramsCached('javascript'); // returns virtually instantly since it's now cached +console.log(anagramsCached.cache); // The cached anagrams map +```

    [⬆ Back to top](#table-of-contents) -### once - -Ensures a function is called only once. - -Utilizing a closure, use a flag, `called`, and set it to `true` once the function is called for the first time, preventing it from being called again. In order to allow the function to have its `this` context changed (such as in an event listener), the `function` keyword must be used, and the supplied function must have the context applied. -Allow the function to be supplied with an arbitrary number of arguments using the rest/spread (`...`) operator. - -```js -const once = fn => { - let called = false; - return function(...args) { - if (called) return; - called = true; - return fn.apply(this, args); - }; -}; -``` - +### once + +Ensures a function is called only once. + +Utilizing a closure, use a flag, `called`, and set it to `true` once the function is called for the first time, preventing it from being called again. In order to allow the function to have its `this` context changed (such as in an event listener), the `function` keyword must be used, and the supplied function must have the context applied. +Allow the function to be supplied with an arbitrary number of arguments using the rest/spread (`...`) operator. + +```js +const once = fn => { + let called = false; + return function(...args) { + if (called) return; + called = true; + return fn.apply(this, args); + }; +}; +``` +
    Examples -```js -const startApp = function(event) { - console.log(this, event); // document.body, MouseEvent -}; -document.body.addEventListener('click', once(startApp)); // only runs `startApp` once upon click -``` +```js +const startApp = function(event) { + console.log(this, event); // document.body, MouseEvent +}; +document.body.addEventListener('click', once(startApp)); // only runs `startApp` once upon click +```

    [⬆ Back to top](#table-of-contents) -### runPromisesInSeries - -Runs an array of promises in series. - -Use `Array.reduce()` to create a promise chain, where each promise returns the next promise when resolved. - -```js -const runPromisesInSeries = ps => ps.reduce((p, next) => p.then(next), Promise.resolve()); -``` - +### runPromisesInSeries + +Runs an array of promises in series. + +Use `Array.reduce()` to create a promise chain, where each promise returns the next promise when resolved. + +```js +const runPromisesInSeries = ps => ps.reduce((p, next) => p.then(next), Promise.resolve()); +``` +
    Examples -```js -const delay = d => new Promise(r => setTimeout(r, d)); -runPromisesInSeries([() => delay(1000), () => delay(2000)]); // Executes each promise sequentially, taking a total of 3 seconds to complete -``` +```js +const delay = d => new Promise(r => setTimeout(r, d)); +runPromisesInSeries([() => delay(1000), () => delay(2000)]); // Executes each promise sequentially, taking a total of 3 seconds to complete +```

    [⬆ Back to top](#table-of-contents) -### sleep - -Delays the execution of an asynchronous function. - -Delay executing part of an `async` function, by putting it to sleep, returning a `Promise`. - -```js -const sleep = ms => new Promise(resolve => setTimeout(resolve, ms)); -``` - +### sleep + +Delays the execution of an asynchronous function. + +Delay executing part of an `async` function, by putting it to sleep, returning a `Promise`. + +```js +const sleep = ms => new Promise(resolve => setTimeout(resolve, ms)); +``` +
    Examples -```js -async function sleepyWork() { - console.log("I'm going to sleep for 1 second."); - await sleep(1000); - console.log('I woke up after 1 second.'); -} -``` +```js +async function sleepyWork() { + console.log("I'm going to sleep for 1 second."); + await sleep(1000); + console.log('I woke up after 1 second.'); +} +```
    @@ -2716,23 +2716,23 @@ async function sleepyWork() { --- ## 🔮 Logic -### negate - -Negates a predicate function. - -Take a predicate function and apply the not operator (`!`) to it with its arguments. - -```js -const negate = func => (...args) => !func(...args); -``` - +### negate + +Negates a predicate function. + +Take a predicate function and apply the not operator (`!`) to it with its arguments. + +```js +const negate = func => (...args) => !func(...args); +``` +
    Examples -```js -filter([1, 2, 3, 4, 5, 6], negate(isEven)); // [1, 3, 5] -negate(isOdd)(1); // false -``` +```js +filter([1, 2, 3, 4, 5, 6], negate(isEven)); // [1, 3, 5] +negate(isOdd)(1); // false +```
    @@ -2741,92 +2741,92 @@ negate(isOdd)(1); // false --- ## ➗ Math -### average - -Returns the average of an of two or more numbers. - -Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`, divide by the `length` of the array. - -```js -const average = (...nums) => [...nums].reduce((acc, val) => acc + val, 0) / nums.length; -``` - +### average + +Returns the average of an of two or more numbers. + +Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`, divide by the `length` of the array. + +```js +const average = (...nums) => [...nums].reduce((acc, val) => acc + val, 0) / nums.length; +``` +
    Examples -```js -average(...[1, 2, 3]); // 2 -average(1, 2, 3); // 2 -``` +```js +average(...[1, 2, 3]); // 2 +average(1, 2, 3); // 2 +```

    [⬆ Back to top](#table-of-contents) -### clampNumber - -Clamps `num` within the inclusive range specified by the boundary values `a` and `b`. - -If `num` falls within the range, return `num`. -Otherwise, return the nearest number in the range. - -```js -const clampNumber = (num, a, b) => Math.max(Math.min(num, Math.max(a, b)), Math.min(a, b)); -``` - +### clampNumber + +Clamps `num` within the inclusive range specified by the boundary values `a` and `b`. + +If `num` falls within the range, return `num`. +Otherwise, return the nearest number in the range. + +```js +const clampNumber = (num, a, b) => Math.max(Math.min(num, Math.max(a, b)), Math.min(a, b)); +``` +
    Examples -```js -clampNumber(2, 3, 5); // 3 -clampNumber(1, -1, -5); // -1 -``` +```js +clampNumber(2, 3, 5); // 3 +clampNumber(1, -1, -5); // -1 +```

    [⬆ Back to top](#table-of-contents) -### digitize - -Converts a number to an array of digits. - -Convert the number to a string, using the spread operator (`...`) to build an array. -Use `Array.map()` and `parseInt()` to transform each value to an integer. - -```js -const digitize = n => [...`${n}`].map(i => parseInt(i)); -``` - +### digitize + +Converts a number to an array of digits. + +Convert the number to a string, using the spread operator (`...`) to build an array. +Use `Array.map()` and `parseInt()` to transform each value to an integer. + +```js +const digitize = n => [...`${n}`].map(i => parseInt(i)); +``` +
    Examples -```js -digitize(123); // [1, 2, 3] -``` +```js +digitize(123); // [1, 2, 3] +```

    [⬆ Back to top](#table-of-contents) -### distance - -Returns the distance between two points. - -Use `Math.hypot()` to calculate the Euclidean distance between two points. - -```js -const distance = (x0, y0, x1, y1) => Math.hypot(x1 - x0, y1 - y0); -``` - +### distance + +Returns the distance between two points. + +Use `Math.hypot()` to calculate the Euclidean distance between two points. + +```js +const distance = (x0, y0, x1, y1) => Math.hypot(x1 - x0, y1 - y0); +``` +
    Examples -```js -distance(1, 1, 2, 3); // 2.23606797749979 -``` +```js +distance(1, 1, 2, 3); // 2.23606797749979 +```
    @@ -2886,583 +2886,583 @@ own individual rating by supplying it as the third argument.
    [⬆ Back to top](#table-of-contents) -### factorial - -Calculates the factorial of a number. - -Use recursion. -If `n` is less than or equal to `1`, return `1`. -Otherwise, return the product of `n` and the factorial of `n - 1`. -Throws an exception if `n` is a negative number. - -```js -const factorial = n => - n < 0 - ? (() => { - throw new TypeError('Negative numbers are not allowed!'); - })() - : n <= 1 ? 1 : n * factorial(n - 1); -``` - +### factorial + +Calculates the factorial of a number. + +Use recursion. +If `n` is less than or equal to `1`, return `1`. +Otherwise, return the product of `n` and the factorial of `n - 1`. +Throws an exception if `n` is a negative number. + +```js +const factorial = n => + n < 0 + ? (() => { + throw new TypeError('Negative numbers are not allowed!'); + })() + : n <= 1 ? 1 : n * factorial(n - 1); +``` +
    Examples -```js -factorial(6); // 720 -``` +```js +factorial(6); // 720 +```

    [⬆ Back to top](#table-of-contents) -### fibonacci - -Generates an array, containing the Fibonacci sequence, up until the nth term. - -Create an empty array of the specific length, initializing the first two values (`0` and `1`). -Use `Array.reduce()` to add values into the array, using the sum of the last two values, except for the first two. - -```js -const fibonacci = n => - Array.from({ length: n }).reduce( - (acc, val, i) => acc.concat(i > 1 ? acc[i - 1] + acc[i - 2] : i), - [] - ); -``` - +### fibonacci + +Generates an array, containing the Fibonacci sequence, up until the nth term. + +Create an empty array of the specific length, initializing the first two values (`0` and `1`). +Use `Array.reduce()` to add values into the array, using the sum of the last two values, except for the first two. + +```js +const fibonacci = n => + Array.from({ length: n }).reduce( + (acc, val, i) => acc.concat(i > 1 ? acc[i - 1] + acc[i - 2] : i), + [] + ); +``` +
    Examples -```js -fibonacci(6); // [0, 1, 1, 2, 3, 5] -``` +```js +fibonacci(6); // [0, 1, 1, 2, 3, 5] +```

    [⬆ Back to top](#table-of-contents) -### gcd - -Calculates the greatest common divisor between two or more numbers/arrays. - -The inner `_gcd` function uses recursion. -Base case is when `y` equals `0`. In this case, return `x`. -Otherwise, return the GCD of `y` and the remainder of the division `x/y`. - -```js -const gcd = (...arr) => { - const _gcd = (x, y) => (!y ? x : gcd(y, x % y)); - return [...arr].reduce((a, b) => _gcd(a, b)); -}; -``` - +### gcd + +Calculates the greatest common divisor between two or more numbers/arrays. + +The inner `_gcd` function uses recursion. +Base case is when `y` equals `0`. In this case, return `x`. +Otherwise, return the GCD of `y` and the remainder of the division `x/y`. + +```js +const gcd = (...arr) => { + const _gcd = (x, y) => (!y ? x : gcd(y, x % y)); + return [...arr].reduce((a, b) => _gcd(a, b)); +}; +``` +
    Examples -```js -gcd(8, 36); // 4 -gcd(...[12, 8, 32]); // 4 -``` +```js +gcd(8, 36); // 4 +gcd(...[12, 8, 32]); // 4 +```

    [⬆ Back to top](#table-of-contents) -### geometricProgression - -Initializes an array containing the numbers in the specified range where `start` and `end` are inclusive and the ratio between two terms is `step`. -Returns an error if `step` equals `1`. - -Use `Array.from()`, `Math.log()` and `Math.floor()` to create an array of the desired length, `Array.map()` to fill with the desired values in a range. -Omit the second argument, `start`, to use a default value of `1`. -Omit the third argument, `step`, to use a default value of `2`. - -```js -const geometricProgression = (end, start = 1, step = 2) => - Array.from({ length: Math.floor(Math.log(end / start) / Math.log(step)) + 1 }).map( - (v, i) => start * step ** i - ); -``` - +### geometricProgression + +Initializes an array containing the numbers in the specified range where `start` and `end` are inclusive and the ratio between two terms is `step`. +Returns an error if `step` equals `1`. + +Use `Array.from()`, `Math.log()` and `Math.floor()` to create an array of the desired length, `Array.map()` to fill with the desired values in a range. +Omit the second argument, `start`, to use a default value of `1`. +Omit the third argument, `step`, to use a default value of `2`. + +```js +const geometricProgression = (end, start = 1, step = 2) => + Array.from({ length: Math.floor(Math.log(end / start) / Math.log(step)) + 1 }).map( + (v, i) => start * step ** i + ); +``` +
    Examples -```js -geometricProgression(256); // [1, 2, 4, 8, 16, 32, 64, 128, 256] -geometricProgression(256, 3); // [3, 6, 12, 24, 48, 96, 192] -geometricProgression(256, 1, 4); // [1, 4, 16, 64, 256] -``` +```js +geometricProgression(256); // [1, 2, 4, 8, 16, 32, 64, 128, 256] +geometricProgression(256, 3); // [3, 6, 12, 24, 48, 96, 192] +geometricProgression(256, 1, 4); // [1, 4, 16, 64, 256] +```

    [⬆ Back to top](#table-of-contents) -### hammingDistance - -Calculates the Hamming distance between two values. - -Use XOR operator (`^`) to find the bit difference between the two numbers, convert to a binary string using `toString(2)`. -Count and return the number of `1`s in the string, using `match(/1/g)`. - -```js -const hammingDistance = (num1, num2) => ((num1 ^ num2).toString(2).match(/1/g) || '').length; -``` - +### hammingDistance + +Calculates the Hamming distance between two values. + +Use XOR operator (`^`) to find the bit difference between the two numbers, convert to a binary string using `toString(2)`. +Count and return the number of `1`s in the string, using `match(/1/g)`. + +```js +const hammingDistance = (num1, num2) => ((num1 ^ num2).toString(2).match(/1/g) || '').length; +``` +
    Examples -```js -hammingDistance(2, 3); // 1 -``` +```js +hammingDistance(2, 3); // 1 +```

    [⬆ Back to top](#table-of-contents) -### inRange - -Checks if the given number falls within the given range. - -Use arithmetic comparison to check if the given number is in the specified range. -If the second parameter, `end`, is not specified, the range is considered to be from `0` to `start`. - -```js -const inRange = (n, start, end = null) => { - if (end && start > end) end = [start, (start = end)][0]; - return end == null ? n >= 0 && n < start : n >= start && n < end; -}; -``` - +### inRange + +Checks if the given number falls within the given range. + +Use arithmetic comparison to check if the given number is in the specified range. +If the second parameter, `end`, is not specified, the range is considered to be from `0` to `start`. + +```js +const inRange = (n, start, end = null) => { + if (end && start > end) end = [start, (start = end)][0]; + return end == null ? n >= 0 && n < start : n >= start && n < end; +}; +``` +
    Examples -```js -inRange(3, 2, 5); // true -inRange(3, 4); // true -inRange(2, 3, 5); // false -inrange(3, 2); // false -``` +```js +inRange(3, 2, 5); // true +inRange(3, 4); // true +inRange(2, 3, 5); // false +inrange(3, 2); // false +```

    [⬆ Back to top](#table-of-contents) -### isDivisible - -Checks if the first numeric argument is divisible by the second one. - -Use the modulo operator (`%`) to check if the remainder is equal to `0`. - -```js -const isDivisible = (dividend, divisor) => dividend % divisor === 0; -``` - +### isDivisible + +Checks if the first numeric argument is divisible by the second one. + +Use the modulo operator (`%`) to check if the remainder is equal to `0`. + +```js +const isDivisible = (dividend, divisor) => dividend % divisor === 0; +``` +
    Examples -```js -isDivisible(6, 3); // true -``` +```js +isDivisible(6, 3); // true +```

    [⬆ Back to top](#table-of-contents) -### isEven - -Returns `true` if the given number is even, `false` otherwise. - -Checks whether a number is odd or even using the modulo (`%`) operator. -Returns `true` if the number is even, `false` if the number is odd. - -```js -const isEven = num => num % 2 === 0; -``` - +### isEven + +Returns `true` if the given number is even, `false` otherwise. + +Checks whether a number is odd or even using the modulo (`%`) operator. +Returns `true` if the number is even, `false` if the number is odd. + +```js +const isEven = num => num % 2 === 0; +``` +
    Examples -```js -isEven(3); // false -``` +```js +isEven(3); // false +```

    [⬆ Back to top](#table-of-contents) -### isPrime - -Checks if the provided integer is a prime number. - -Check numbers from `2` to the square root of the given number. -Return `false` if any of them divides the given number, else return `true`, unless the number is less than `2`. - -```js -const isPrime = num => { - const boundary = Math.floor(Math.sqrt(num)); - for (var i = 2; i <= boundary; i++) if (num % i == 0) return false; - return num >= 2; -}; -``` - +### isPrime + +Checks if the provided integer is a prime number. + +Check numbers from `2` to the square root of the given number. +Return `false` if any of them divides the given number, else return `true`, unless the number is less than `2`. + +```js +const isPrime = num => { + const boundary = Math.floor(Math.sqrt(num)); + for (var i = 2; i <= boundary; i++) if (num % i == 0) return false; + return num >= 2; +}; +``` +
    Examples -```js -isPrime(11); // true -``` +```js +isPrime(11); // true +```

    [⬆ Back to top](#table-of-contents) -### lcm - -Returns the least common multiple of two or more numbers. - -Use the greatest common divisor (GCD) formula and `Math.abs()` to determine the least common multiple. -The GCD formula uses recursion. - -```js -const lcm = (...arr) => { - const gcd = (x, y) => (!y ? x : gcd(y, x % y)); - const _lcm = (x, y) => x * y / gcd(x, y); - return [...arr].reduce((a, b) => _lcm(a, b)); -}; -``` - +### lcm + +Returns the least common multiple of two or more numbers. + +Use the greatest common divisor (GCD) formula and `Math.abs()` to determine the least common multiple. +The GCD formula uses recursion. + +```js +const lcm = (...arr) => { + const gcd = (x, y) => (!y ? x : gcd(y, x % y)); + const _lcm = (x, y) => x * y / gcd(x, y); + return [...arr].reduce((a, b) => _lcm(a, b)); +}; +``` +
    Examples -```js -lcm(12, 7); // 84 -lcm(...[1, 3, 4, 5]); // 60 -``` +```js +lcm(12, 7); // 84 +lcm(...[1, 3, 4, 5]); // 60 +```

    [⬆ Back to top](#table-of-contents) -### luhnCheck - -Implementation of the [Luhn Algorithm](https://en.wikipedia.org/wiki/Luhn_algorithm) used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, National Provider Identifier numbers etc. - -Use `String.split('')`, `Array.reverse()` and `Array.map()` in combination with `parseInt()` to obtain an array of digits. -Use `Array.splice(0,1)` to obtain the last digit. -Use `Array.reduce()` to implement the Luhn Algorithm. -Return `true` if `sum` is divisible by `10`, `false` otherwise. - - -```js -const luhnCheck = num => { - let arr = (num + '') - .split('') - .reverse() - .map(x => parseInt(x)); - let lastDigit = arr.splice(0, 1)[0]; - let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + (val * 2) % 9 || 9), 0); - sum += lastDigit; - return sum % 10 === 0; -}; -``` - +### luhnCheck + +Implementation of the [Luhn Algorithm](https://en.wikipedia.org/wiki/Luhn_algorithm) used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, National Provider Identifier numbers etc. + +Use `String.split('')`, `Array.reverse()` and `Array.map()` in combination with `parseInt()` to obtain an array of digits. +Use `Array.splice(0,1)` to obtain the last digit. +Use `Array.reduce()` to implement the Luhn Algorithm. +Return `true` if `sum` is divisible by `10`, `false` otherwise. + + +```js +const luhnCheck = num => { + let arr = (num + '') + .split('') + .reverse() + .map(x => parseInt(x)); + let lastDigit = arr.splice(0, 1)[0]; + let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + (val * 2) % 9 || 9), 0); + sum += lastDigit; + return sum % 10 === 0; +}; +``` +
    Examples -```js -luhnCheck('4485275742308327'); // true -luhnCheck(6011329933655299); // true -luhnCheck(123456789); // false -``` +```js +luhnCheck('4485275742308327'); // true +luhnCheck(6011329933655299); // true +luhnCheck(123456789); // false +```

    [⬆ Back to top](#table-of-contents) -### median - -Returns the median of an array of numbers. - -Find the middle of the array, use `Array.sort()` to sort the values. -Return the number at the midpoint if `length` is odd, otherwise the average of the two middle numbers. - -```js -const median = arr => { - const mid = Math.floor(arr.length / 2), - nums = [...arr].sort((a, b) => a - b); - return arr.length % 2 !== 0 ? nums[mid] : (nums[mid - 1] + nums[mid]) / 2; -}; -``` - +### median + +Returns the median of an array of numbers. + +Find the middle of the array, use `Array.sort()` to sort the values. +Return the number at the midpoint if `length` is odd, otherwise the average of the two middle numbers. + +```js +const median = arr => { + const mid = Math.floor(arr.length / 2), + nums = [...arr].sort((a, b) => a - b); + return arr.length % 2 !== 0 ? nums[mid] : (nums[mid - 1] + nums[mid]) / 2; +}; +``` +
    Examples -```js -median([5, 6, 50, 1, -5]); // 5 -``` +```js +median([5, 6, 50, 1, -5]); // 5 +```

    [⬆ Back to top](#table-of-contents) -### percentile - -Uses the percentile formula to calculate how many numbers in the given array are less or equal to the given value. - -Use `Array.reduce()` to calculate how many numbers are below the value and how many are the same value and apply the percentile formula. - -```js -const percentile = (arr, val) => - 100 * arr.reduce((acc, v) => acc + (v < val ? 1 : 0) + (v === val ? 0.5 : 0), 0) / arr.length; -``` - +### percentile + +Uses the percentile formula to calculate how many numbers in the given array are less or equal to the given value. + +Use `Array.reduce()` to calculate how many numbers are below the value and how many are the same value and apply the percentile formula. + +```js +const percentile = (arr, val) => + 100 * arr.reduce((acc, v) => acc + (v < val ? 1 : 0) + (v === val ? 0.5 : 0), 0) / arr.length; +``` +
    Examples -```js -percentile([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 6); // 55 -``` +```js +percentile([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 6); // 55 +```

    [⬆ Back to top](#table-of-contents) -### powerset - -Returns the powerset of a given array of numbers. - -Use `Array.reduce()` combined with `Array.map()` to iterate over elements and combine into an array containing all combinations. - -```js -const powerset = arr => arr.reduce((a, v) => a.concat(a.map(r => [v].concat(r))), [[]]); -``` - +### powerset + +Returns the powerset of a given array of numbers. + +Use `Array.reduce()` combined with `Array.map()` to iterate over elements and combine into an array containing all combinations. + +```js +const powerset = arr => arr.reduce((a, v) => a.concat(a.map(r => [v].concat(r))), [[]]); +``` +
    Examples -```js -powerset([1, 2]); // [[], [1], [2], [2,1]] -``` +```js +powerset([1, 2]); // [[], [1], [2], [2,1]] +```

    [⬆ Back to top](#table-of-contents) -### primes - -Generates primes up to a given number, using the Sieve of Eratosthenes. - -Generate an array from `2` to the given number. Use `Array.filter()` to filter out the values divisible by any number from `2` to the square root of the provided number. - -```js -const primes = num => { - let arr = Array.from({ length: num - 1 }).map((x, i) => i + 2), - sqroot = Math.floor(Math.sqrt(num)), - numsTillSqroot = Array.from({ length: sqroot - 1 }).map((x, i) => i + 2); - numsTillSqroot.forEach(x => (arr = arr.filter(y => y % x !== 0 || y == x))); - return arr; -}; -``` - +### primes + +Generates primes up to a given number, using the Sieve of Eratosthenes. + +Generate an array from `2` to the given number. Use `Array.filter()` to filter out the values divisible by any number from `2` to the square root of the provided number. + +```js +const primes = num => { + let arr = Array.from({ length: num - 1 }).map((x, i) => i + 2), + sqroot = Math.floor(Math.sqrt(num)), + numsTillSqroot = Array.from({ length: sqroot - 1 }).map((x, i) => i + 2); + numsTillSqroot.forEach(x => (arr = arr.filter(y => y % x !== 0 || y == x))); + return arr; +}; +``` +
    Examples -```js -primes(10); // [2,3,5,7] -``` +```js +primes(10); // [2,3,5,7] +```

    [⬆ Back to top](#table-of-contents) -### randomIntegerInRange - -Returns a random integer in the specified range. - -Use `Math.random()` to generate a random number and map it to the desired range, using `Math.floor()` to make it an integer. - -```js -const randomIntegerInRange = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min; -``` - +### randomIntegerInRange + +Returns a random integer in the specified range. + +Use `Math.random()` to generate a random number and map it to the desired range, using `Math.floor()` to make it an integer. + +```js +const randomIntegerInRange = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min; +``` +
    Examples -```js -randomIntegerInRange(0, 5); // 2 -``` +```js +randomIntegerInRange(0, 5); // 2 +```

    [⬆ Back to top](#table-of-contents) -### randomNumberInRange - -Returns a random number in the specified range. - -Use `Math.random()` to generate a random value, map it to the desired range using multiplication. - -```js -const randomNumberInRange = (min, max) => Math.random() * (max - min) + min; -``` - +### randomNumberInRange + +Returns a random number in the specified range. + +Use `Math.random()` to generate a random value, map it to the desired range using multiplication. + +```js +const randomNumberInRange = (min, max) => Math.random() * (max - min) + min; +``` +
    Examples -```js -randomNumberInRange(2, 10); // 6.0211363285087005 -``` +```js +randomNumberInRange(2, 10); // 6.0211363285087005 +```

    [⬆ Back to top](#table-of-contents) -### round - -Rounds a number to a specified amount of digits. - -Use `Math.round()` and template literals to round the number to the specified number of digits. -Omit the second argument, `decimals` to round to an integer. - -```js -const round = (n, decimals = 0) => Number(`${Math.round(`${n}e${decimals}`)}e-${decimals}`); -``` - +### round + +Rounds a number to a specified amount of digits. + +Use `Math.round()` and template literals to round the number to the specified number of digits. +Omit the second argument, `decimals` to round to an integer. + +```js +const round = (n, decimals = 0) => Number(`${Math.round(`${n}e${decimals}`)}e-${decimals}`); +``` +
    Examples -```js -round(1.005, 2); // 1.01 -``` +```js +round(1.005, 2); // 1.01 +```

    [⬆ Back to top](#table-of-contents) -### sbdm - -Hashes the input string into a whole number. - -Use `String.split('')` and `Array.reduce()` to create a hash of the input string, utilizing bit shifting. - -```js -const sdbm = str => { - let arr = str.split(''); - return arr.reduce( - (hashCode, currentVal) => - (hashCode = currentVal.charCodeAt(0) + (hashCode << 6) + (hashCode << 16) - hashCode), - 0 - ); -}; -``` - +### sbdm + +Hashes the input string into a whole number. + +Use `String.split('')` and `Array.reduce()` to create a hash of the input string, utilizing bit shifting. + +```js +const sdbm = str => { + let arr = str.split(''); + return arr.reduce( + (hashCode, currentVal) => + (hashCode = currentVal.charCodeAt(0) + (hashCode << 6) + (hashCode << 16) - hashCode), + 0 + ); +}; +``` +
    Examples -```js -console.log(sdbm('name')); // -3521204949 -``` +```js +console.log(sdbm('name')); // -3521204949 +```

    [⬆ Back to top](#table-of-contents) -### standardDeviation - -Returns the standard deviation of an array of numbers. - -Use `Array.reduce()` to calculate the mean, variance and the sum of the variance of the values, the variance of the values, then -determine the standard deviation. -You can omit the second argument to get the sample standard deviation or set it to `true` to get the population standard deviation. - -```js -const standardDeviation = (arr, usePopulation = false) => { - const mean = arr.reduce((acc, val) => acc + val, 0) / arr.length; - return Math.sqrt( - arr.reduce((acc, val) => acc.concat((val - mean) ** 2), []).reduce((acc, val) => acc + val, 0) / - (arr.length - (usePopulation ? 0 : 1)) - ); -}; -``` - +### standardDeviation + +Returns the standard deviation of an array of numbers. + +Use `Array.reduce()` to calculate the mean, variance and the sum of the variance of the values, the variance of the values, then +determine the standard deviation. +You can omit the second argument to get the sample standard deviation or set it to `true` to get the population standard deviation. + +```js +const standardDeviation = (arr, usePopulation = false) => { + const mean = arr.reduce((acc, val) => acc + val, 0) / arr.length; + return Math.sqrt( + arr.reduce((acc, val) => acc.concat((val - mean) ** 2), []).reduce((acc, val) => acc + val, 0) / + (arr.length - (usePopulation ? 0 : 1)) + ); +}; +``` +
    Examples -```js -standardDeviation([10, 2, 38, 23, 38, 23, 21]); // 13.284434142114991 (sample) -standardDeviation([10, 2, 38, 23, 38, 23, 21], true); // 12.29899614287479 (population) -``` +```js +standardDeviation([10, 2, 38, 23, 38, 23, 21]); // 13.284434142114991 (sample) +standardDeviation([10, 2, 38, 23, 38, 23, 21], true); // 12.29899614287479 (population) +```

    [⬆ Back to top](#table-of-contents) -### sum - -Returns the sum of two or more numbers/arrays. - -Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`. - -```js -const sum = (...arr) => [...arr].reduce((acc, val) => acc + val, 0); -``` - +### sum + +Returns the sum of two or more numbers/arrays. + +Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`. + +```js +const sum = (...arr) => [...arr].reduce((acc, val) => acc + val, 0); +``` +
    Examples -```js -sum(...[1, 2, 3, 4]); // 10 -``` +```js +sum(...[1, 2, 3, 4]); // 10 +```

    [⬆ Back to top](#table-of-contents) -### sumPower - -Returns the sum of the powers of all the numbers from `start` to `end` (both inclusive). - -Use `Array.fill()` to create an array of all the numbers in the target range, `Array.map()` and the exponent operator (`**`) to raise them to `power` and `Array.reduce()` to add them together. -Omit the second argument, `power`, to use a default power of `2`. -Omit the third argument, `start`, to use a default starting value of `1`. - -```js -const sumPower = (end, power = 2, start = 1) => - Array(end + 1 - start) - .fill(0) - .map((x, i) => (i + start) ** power) - .reduce((a, b) => a + b, 0); -``` - +### sumPower + +Returns the sum of the powers of all the numbers from `start` to `end` (both inclusive). + +Use `Array.fill()` to create an array of all the numbers in the target range, `Array.map()` and the exponent operator (`**`) to raise them to `power` and `Array.reduce()` to add them together. +Omit the second argument, `power`, to use a default power of `2`. +Omit the third argument, `start`, to use a default starting value of `1`. + +```js +const sumPower = (end, power = 2, start = 1) => + Array(end + 1 - start) + .fill(0) + .map((x, i) => (i + start) ** power) + .reduce((a, b) => a + b, 0); +``` +
    Examples -```js -sumPower(10); // 385 -sumPower(10, 3); //3025 -sumPower(10, 3, 5); //2925 -``` +```js +sumPower(10); // 385 +sumPower(10, 3); //3025 +sumPower(10, 3, 5); //2925 +```
    @@ -3471,159 +3471,159 @@ sumPower(10, 3, 5); //2925 --- ## 📦 Node -### hasFlags - -Check if the current process's arguments contain the specified flags. - -Use `Array.every()` and `Array.includes()` to check if `process.argv` contains all the specified flags. -Use a regular expression to test if the specified flags are prefixed with `-` or `--` and prefix them accordingly. - -```js -const hasFlags = (...flags) => - flags.every(flag => process.argv.includes(/^-{1,2}/.test(flag) ? flag : '--' + flag)); -``` - +### hasFlags + +Check if the current process's arguments contain the specified flags. + +Use `Array.every()` and `Array.includes()` to check if `process.argv` contains all the specified flags. +Use a regular expression to test if the specified flags are prefixed with `-` or `--` and prefix them accordingly. + +```js +const hasFlags = (...flags) => + flags.every(flag => process.argv.includes(/^-{1,2}/.test(flag) ? flag : '--' + flag)); +``` +
    Examples -```js -// node myScript.js -s --test --cool=true -hasFlags('-s'); // true -hasFlags('--test', 'cool=true', '-s'); // true -hasFlags('special'); // false -``` +```js +// node myScript.js -s --test --cool=true +hasFlags('-s'); // true +hasFlags('--test', 'cool=true', '-s'); // true +hasFlags('special'); // false +```

    [⬆ Back to top](#table-of-contents) -### isTravisCI - -Checks if the current environment is [Travis CI](https://travis-ci.org/). - -Checks if the current environment has the `TRAVIS` and `CI` environment variables ([reference](https://docs.travis-ci.com/user/environment-variables/#Default-Environment-Variables)). - -```js -const isTravisCI = () => 'TRAVIS' in process.env && 'CI' in process.env; -``` - +### isTravisCI + +Checks if the current environment is [Travis CI](https://travis-ci.org/). + +Checks if the current environment has the `TRAVIS` and `CI` environment variables ([reference](https://docs.travis-ci.com/user/environment-variables/#Default-Environment-Variables)). + +```js +const isTravisCI = () => 'TRAVIS' in process.env && 'CI' in process.env; +``` +
    Examples -```js -isTravisCI(); // true (if code is running on Travis CI) -``` +```js +isTravisCI(); // true (if code is running on Travis CI) +```

    [⬆ Back to top](#table-of-contents) -### JSONToFile - -Writes a JSON object to a file. - -Use `fs.writeFile()`, template literals and `JSON.stringify()` to write a `json` object to a `.json` file. - -```js -const fs = require('fs'); -const JSONToFile = (obj, filename) => - fs.writeFile(`${filename}.json`, JSON.stringify(obj, null, 2)); -``` - +### JSONToFile + +Writes a JSON object to a file. + +Use `fs.writeFile()`, template literals and `JSON.stringify()` to write a `json` object to a `.json` file. + +```js +const fs = require('fs'); +const JSONToFile = (obj, filename) => + fs.writeFile(`${filename}.json`, JSON.stringify(obj, null, 2)); +``` +
    Examples -```js -JSONToFile({ test: 'is passed' }, 'testJsonFile'); // writes the object to 'testJsonFile.json' -``` +```js +JSONToFile({ test: 'is passed' }, 'testJsonFile'); // writes the object to 'testJsonFile.json' +```

    [⬆ Back to top](#table-of-contents) -### readFileLines - -Returns an array of lines from the specified file. - -Use `readFileSync` function in `fs` node package to create a `Buffer` from a file. -convert buffer to string using `toString(encoding)` function. -creating an array from contents of file by `split`ing file content line by line (each `\n`). - -```js -const fs = require('fs'); -const readFileLines = filename => - fs - .readFileSync(filename) - .toString('UTF8') - .split('\n'); -``` - +### readFileLines + +Returns an array of lines from the specified file. + +Use `readFileSync` function in `fs` node package to create a `Buffer` from a file. +convert buffer to string using `toString(encoding)` function. +creating an array from contents of file by `split`ing file content line by line (each `\n`). + +```js +const fs = require('fs'); +const readFileLines = filename => + fs + .readFileSync(filename) + .toString('UTF8') + .split('\n'); +``` +
    Examples -```js -/* -contents of test.txt : - line1 - line2 - line3 - ___________________________ -*/ -let arr = readFileLines('test.txt'); -console.log(arr); // ['line1', 'line2', 'line3'] -``` - +```js +/* +contents of test.txt : + line1 + line2 + line3 + ___________________________ +*/ +let arr = readFileLines('test.txt'); +console.log(arr); // ['line1', 'line2', 'line3'] +``` +

    [⬆ Back to top](#table-of-contents) -### untildify - -Converts a tilde path to an absolute path. - -Use `String.replace()` with a regular expression and `OS.homedir()` to replace the `~` in the start of the path with the home directory. - -```js -const untildify = str => str.replace(/^~($|\/|\\)/, `${require('os').homedir()}$1`); -``` - +### untildify + +Converts a tilde path to an absolute path. + +Use `String.replace()` with a regular expression and `OS.homedir()` to replace the `~` in the start of the path with the home directory. + +```js +const untildify = str => str.replace(/^~($|\/|\\)/, `${require('os').homedir()}$1`); +``` +
    Examples -```js -untildify('~/node'); // '/Users/aUser/node' -``` +```js +untildify('~/node'); // '/Users/aUser/node' +```

    [⬆ Back to top](#table-of-contents) -### UUIDGeneratorNode - -Generates a UUID in Node.JS. - -Use `crypto` API to generate a UUID, compliant with [RFC4122](https://www.ietf.org/rfc/rfc4122.txt) version 4. - -```js -const crypto = require('crypto'); -const UUIDGeneratorNode = () => - ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c => - (c ^ (crypto.randomBytes(1)[0] & (15 >> (c / 4)))).toString(16) - ); -``` - +### UUIDGeneratorNode + +Generates a UUID in Node.JS. + +Use `crypto` API to generate a UUID, compliant with [RFC4122](https://www.ietf.org/rfc/rfc4122.txt) version 4. + +```js +const crypto = require('crypto'); +const UUIDGeneratorNode = () => + ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c => + (c ^ (crypto.randomBytes(1)[0] & (15 >> (c / 4)))).toString(16) + ); +``` +
    Examples -```js -UUIDGeneratorNode(); // '79c7c136-60ee-40a2-beb2-856f1feabefc' -``` +```js +UUIDGeneratorNode(); // '79c7c136-60ee-40a2-beb2-856f1feabefc' +```
    @@ -3632,268 +3632,268 @@ UUIDGeneratorNode(); // '79c7c136-60ee-40a2-beb2-856f1feabefc' --- ## 🗃️ Object -### cleanObj - -Removes any properties except the ones specified from a JSON object. - -Use `Object.keys()` method to loop over given JSON object and deleting keys that are not included in given array. -If you pass a special key,`childIndicator`, it will search deeply apply the function to inner objects, too. - -```js -const cleanObj = (obj, keysToKeep = [], childIndicator) => { - Object.keys(obj).forEach(key => { - if (key === childIndicator) { - cleanObj(obj[key], keysToKeep, childIndicator); - } else if (!keysToKeep.includes(key)) { - delete obj[key]; - } - }); - return obj; -}; -``` - +### cleanObj + +Removes any properties except the ones specified from a JSON object. + +Use `Object.keys()` method to loop over given JSON object and deleting keys that are not included in given array. +If you pass a special key,`childIndicator`, it will search deeply apply the function to inner objects, too. + +```js +const cleanObj = (obj, keysToKeep = [], childIndicator) => { + Object.keys(obj).forEach(key => { + if (key === childIndicator) { + cleanObj(obj[key], keysToKeep, childIndicator); + } else if (!keysToKeep.includes(key)) { + delete obj[key]; + } + }); + return obj; +}; +``` +
    Examples -```js -const testObj = { a: 1, b: 2, children: { a: 1, b: 2 } }; -cleanObj(testObj, ['a'], 'children'); // { a: 1, children : { a: 1}} -``` +```js +const testObj = { a: 1, b: 2, children: { a: 1, b: 2 } }; +cleanObj(testObj, ['a'], 'children'); // { a: 1, children : { a: 1}} +```

    [⬆ Back to top](#table-of-contents) -### invertKeyValues - -Inverts the key-value pairs of an object, without mutating it. - -Use `Object.keys()` and `Array.reduce()` to invert the key-value pairs of an object. - -```js -const invertKeyValues = obj => - Object.keys(obj).reduce((acc, key) => { - acc[obj[key]] = key; - return acc; - }, {}); -``` - +### invertKeyValues + +Inverts the key-value pairs of an object, without mutating it. + +Use `Object.keys()` and `Array.reduce()` to invert the key-value pairs of an object. + +```js +const invertKeyValues = obj => + Object.keys(obj).reduce((acc, key) => { + acc[obj[key]] = key; + return acc; + }, {}); +``` +
    Examples -```js -invertKeyValues({ name: 'John', age: 20 }); // { 20: 'age', John: 'name' } -``` +```js +invertKeyValues({ name: 'John', age: 20 }); // { 20: 'age', John: 'name' } +```

    [⬆ Back to top](#table-of-contents) -### lowercaseKeys - -Creates a new object from the specified object, where all the keys are in lowercase. - -Use `Object.keys()` and `Array.reduce()` to create a new object from the specified object. -Convert each key in the original object to lowercase, using `String.toLowerCase()`. - -```js -const lowercaseKeys = obj => - Object.keys(obj).reduce((acc, key) => { - acc[key.toLowerCase()] = obj[key]; - return acc; - }, {}); -``` - +### lowercaseKeys + +Creates a new object from the specified object, where all the keys are in lowercase. + +Use `Object.keys()` and `Array.reduce()` to create a new object from the specified object. +Convert each key in the original object to lowercase, using `String.toLowerCase()`. + +```js +const lowercaseKeys = obj => + Object.keys(obj).reduce((acc, key) => { + acc[key.toLowerCase()] = obj[key]; + return acc; + }, {}); +``` +
    Examples -```js -const myObj = { Name: 'Adam', sUrnAME: 'Smith' }; -const myObjLower = lowercaseKeys(myObj); // {name: 'Adam', surname: 'Smith'}; -``` +```js +const myObj = { Name: 'Adam', sUrnAME: 'Smith' }; +const myObjLower = lowercaseKeys(myObj); // {name: 'Adam', surname: 'Smith'}; +```

    [⬆ Back to top](#table-of-contents) -### objectFromPairs - -Creates an object from the given key-value pairs. - -Use `Array.reduce()` to create and combine key-value pairs. - -```js -const objectFromPairs = arr => arr.reduce((a, v) => ((a[v[0]] = v[1]), a), {}); -``` - +### objectFromPairs + +Creates an object from the given key-value pairs. + +Use `Array.reduce()` to create and combine key-value pairs. + +```js +const objectFromPairs = arr => arr.reduce((a, v) => ((a[v[0]] = v[1]), a), {}); +``` +
    Examples -```js -objectFromPairs([['a', 1], ['b', 2]]); // {a: 1, b: 2} -``` +```js +objectFromPairs([['a', 1], ['b', 2]]); // {a: 1, b: 2} +```

    [⬆ Back to top](#table-of-contents) -### objectToPairs - -Creates an array of key-value pair arrays from an object. - -Use `Object.keys()` and `Array.map()` to iterate over the object's keys and produce an array with key-value pairs. - -```js -const objectToPairs = obj => Object.keys(obj).map(k => [k, obj[k]]); -``` - +### objectToPairs + +Creates an array of key-value pair arrays from an object. + +Use `Object.keys()` and `Array.map()` to iterate over the object's keys and produce an array with key-value pairs. + +```js +const objectToPairs = obj => Object.keys(obj).map(k => [k, obj[k]]); +``` +
    Examples -```js -objectToPairs({ a: 1, b: 2 }); // [['a',1],['b',2]]) -``` +```js +objectToPairs({ a: 1, b: 2 }); // [['a',1],['b',2]]) +```

    [⬆ Back to top](#table-of-contents) -### orderBy - -Returns a sorted array of objects ordered by properties and orders. - -Uses `Array.sort()`, `Array.reduce()` on the `props` array with a default value of `0`, use array destructuring to swap the properties position depending on the order passed. -If no `orders` array is passed it sort by `'asc'` by default. - -```js -const orderBy = (arr, props, orders) => - [...arr].sort((a, b) => - props.reduce((acc, prop, i) => { - if (acc === 0) { - const [p1, p2] = orders && orders[i] === 'desc' ? [b[prop], a[prop]] : [a[prop], b[prop]]; - acc = p1 > p2 ? 1 : p1 < p2 ? -1 : 0; - } - return acc; - }, 0) - ); -``` - +### orderBy + +Returns a sorted array of objects ordered by properties and orders. + +Uses `Array.sort()`, `Array.reduce()` on the `props` array with a default value of `0`, use array destructuring to swap the properties position depending on the order passed. +If no `orders` array is passed it sort by `'asc'` by default. + +```js +const orderBy = (arr, props, orders) => + [...arr].sort((a, b) => + props.reduce((acc, prop, i) => { + if (acc === 0) { + const [p1, p2] = orders && orders[i] === 'desc' ? [b[prop], a[prop]] : [a[prop], b[prop]]; + acc = p1 > p2 ? 1 : p1 < p2 ? -1 : 0; + } + return acc; + }, 0) + ); +``` +
    Examples -```js -const users = [{ name: 'fred', age: 48 }, { name: 'barney', age: 36 }, { name: 'fred', age: 40 }]; -orderBy(users, ['name', 'age'], ['asc', 'desc']); // [{name: 'barney', age: 36}, {name: 'fred', age: 48}, {name: 'fred', age: 40}] -orderBy(users, ['name', 'age']); // [{name: 'barney', age: 36}, {name: 'fred', age: 40}, {name: 'fred', age: 48}] -``` +```js +const users = [{ name: 'fred', age: 48 }, { name: 'barney', age: 36 }, { name: 'fred', age: 40 }]; +orderBy(users, ['name', 'age'], ['asc', 'desc']); // [{name: 'barney', age: 36}, {name: 'fred', age: 48}, {name: 'fred', age: 40}] +orderBy(users, ['name', 'age']); // [{name: 'barney', age: 36}, {name: 'fred', age: 40}, {name: 'fred', age: 48}] +```

    [⬆ Back to top](#table-of-contents) -### select - -Retrieve a property indicated by the selector from an object. - -If the property does not exists returns `undefined`. - -```js -const select = (from, selector) => - selector.split('.').reduce((prev, cur) => prev && prev[cur], from); -``` - +### select + +Retrieve a property indicated by the selector from an object. + +If the property does not exists returns `undefined`. + +```js +const select = (from, selector) => + selector.split('.').reduce((prev, cur) => prev && prev[cur], from); +``` +
    Examples -```js -const obj = { selector: { to: { val: 'val to select' } } }; -select(obj, 'selector.to.val'); // 'val to select' -``` +```js +const obj = { selector: { to: { val: 'val to select' } } }; +select(obj, 'selector.to.val'); // 'val to select' +```

    [⬆ Back to top](#table-of-contents) -### shallowClone - -Creates a shallow clone of an object. - -Use `Object.assign()` and an empty object (`{}`) to create a shallow clone of the original. - -```js -const shallowClone = obj => Object.assign({}, obj); -``` - +### shallowClone + +Creates a shallow clone of an object. + +Use `Object.assign()` and an empty object (`{}`) to create a shallow clone of the original. + +```js +const shallowClone = obj => Object.assign({}, obj); +``` +
    Examples -```js -const a = { x: true, y: 1 }; -const b = shallowClone(a); // a !== b -``` +```js +const a = { x: true, y: 1 }; +const b = shallowClone(a); // a !== b +```

    [⬆ Back to top](#table-of-contents) -### size - -Get size of arrays, objects or strings. - -Get type of `val` (`array`, `object` or `string`). -Use `length` property for arrays. -Use `length` or `size` value if available or number of keys for objects. -Use `size` of a [`Blob` object](https://developer.mozilla.org/en-US/docs/Web/API/Blob) created from `val` for strings. - -Split strings into array of characters with `split('')` and return its length. - -```js -const size = val => - Array.isArray(val) - ? val.length - : val && typeof val === 'object' - ? val.size || val.length || Object.keys(val).length - : typeof val === 'string' ? new Blob([val]).size : 0; -``` - +### size + +Get size of arrays, objects or strings. + +Get type of `val` (`array`, `object` or `string`). +Use `length` property for arrays. +Use `length` or `size` value if available or number of keys for objects. +Use `size` of a [`Blob` object](https://developer.mozilla.org/en-US/docs/Web/API/Blob) created from `val` for strings. + +Split strings into array of characters with `split('')` and return its length. + +```js +const size = val => + Array.isArray(val) + ? val.length + : val && typeof val === 'object' + ? val.size || val.length || Object.keys(val).length + : typeof val === 'string' ? new Blob([val]).size : 0; +``` +
    Examples -```js -size([1, 2, 3, 4, 5]); // 5 -size('size'); // 4 -size({ one: 1, two: 2, three: 3 }); // 3 -``` +```js +size([1, 2, 3, 4, 5]); // 5 +size('size'); // 4 +size({ one: 1, two: 2, three: 3 }); // 3 +```

    [⬆ Back to top](#table-of-contents) -### truthCheckCollection - -Checks if the predicate (second argument) is truthy on all elements of a collection (first argument). - -Use `Array.every()` to check if each passed object has the specified property and if it returns a truthy value. - -```js -const truthCheckCollection = (collection, pre) => collection.every(obj => obj[pre]); -``` - +### truthCheckCollection + +Checks if the predicate (second argument) is truthy on all elements of a collection (first argument). + +Use `Array.every()` to check if each passed object has the specified property and if it returns a truthy value. + +```js +const truthCheckCollection = (collection, pre) => collection.every(obj => obj[pre]); +``` +
    Examples -```js -truthCheckCollection([{ user: 'Tinky-Winky', sex: 'male' }, { user: 'Dipsy', sex: 'male' }], 'sex'); // true -``` +```js +truthCheckCollection([{ user: 'Tinky-Winky', sex: 'male' }, { user: 'Dipsy', sex: 'male' }], 'sex'); // true +```
    @@ -3902,626 +3902,626 @@ truthCheckCollection([{ user: 'Tinky-Winky', sex: 'male' }, { user: 'Dipsy', sex --- ## 📜 String -### anagrams - -⚠️ **WARNING**: This function's execution time increases exponentially with each character. Anything more than 8 to 10 characters will cause your browser to hang as it tries to solve all the different combinations. - -Generates all anagrams of a string (contains duplicates). - -Use recursion. -For each letter in the given string, create all the partial anagrams for the rest of its letters. -Use `Array.map()` to combine the letter with each partial anagram, then `Array.reduce()` to combine all anagrams in one array. -Base cases are for string `length` equal to `2` or `1`. - -```js -const anagrams = str => { - if (str.length <= 2) return str.length === 2 ? [str, str[1] + str[0]] : [str]; - return str - .split('') - .reduce( - (acc, letter, i) => - acc.concat(anagrams(str.slice(0, i) + str.slice(i + 1)).map(val => letter + val)), - [] - ); -}; -``` - +### anagrams + +⚠️ **WARNING**: This function's execution time increases exponentially with each character. Anything more than 8 to 10 characters will cause your browser to hang as it tries to solve all the different combinations. + +Generates all anagrams of a string (contains duplicates). + +Use recursion. +For each letter in the given string, create all the partial anagrams for the rest of its letters. +Use `Array.map()` to combine the letter with each partial anagram, then `Array.reduce()` to combine all anagrams in one array. +Base cases are for string `length` equal to `2` or `1`. + +```js +const anagrams = str => { + if (str.length <= 2) return str.length === 2 ? [str, str[1] + str[0]] : [str]; + return str + .split('') + .reduce( + (acc, letter, i) => + acc.concat(anagrams(str.slice(0, i) + str.slice(i + 1)).map(val => letter + val)), + [] + ); +}; +``` +
    Examples -```js -anagrams('abc'); // ['abc','acb','bac','bca','cab','cba'] -``` +```js +anagrams('abc'); // ['abc','acb','bac','bca','cab','cba'] +```

    [⬆ Back to top](#table-of-contents) -### byteSize - -Returns the length of a string in bytes. - -Convert a given string to a [`Blob` Object](https://developer.mozilla.org/en-US/docs/Web/API/Blob) and find its `size`. - -```js -const byteSize = str => new Blob([str]).size; -``` - +### byteSize + +Returns the length of a string in bytes. + +Convert a given string to a [`Blob` Object](https://developer.mozilla.org/en-US/docs/Web/API/Blob) and find its `size`. + +```js +const byteSize = str => new Blob([str]).size; +``` +
    Examples -```js -byteSize('😀'); // 4 -byteSize('Hello World'); // 11 -``` +```js +byteSize('😀'); // 4 +byteSize('Hello World'); // 11 +```

    [⬆ Back to top](#table-of-contents) -### capitalize - -Capitalizes the first letter of a string. - -Use array destructuring and `String.toUpperCase()` to capitalize first letter, `...rest` to get array of characters after first letter and then `Array.join('')` to make it a string again. -Omit the `lowerRest` parameter to keep the rest of the string intact, or set it to `true` to convert to lowercase. - -```js -const capitalize = ([first, ...rest], lowerRest = false) => - first.toUpperCase() + (lowerRest ? rest.join('').toLowerCase() : rest.join('')); -``` - +### capitalize + +Capitalizes the first letter of a string. + +Use array destructuring and `String.toUpperCase()` to capitalize first letter, `...rest` to get array of characters after first letter and then `Array.join('')` to make it a string again. +Omit the `lowerRest` parameter to keep the rest of the string intact, or set it to `true` to convert to lowercase. + +```js +const capitalize = ([first, ...rest], lowerRest = false) => + first.toUpperCase() + (lowerRest ? rest.join('').toLowerCase() : rest.join('')); +``` +
    Examples -```js -capitalize('fooBar'); // 'FooBar' -capitalize('fooBar', true); // 'Foobar' -``` +```js +capitalize('fooBar'); // 'FooBar' +capitalize('fooBar', true); // 'Foobar' +```

    [⬆ Back to top](#table-of-contents) -### capitalizeEveryWord - -Capitalizes the first letter of every word in a string. - -Use `String.replace()` to match the first character of each word and `String.toUpperCase()` to capitalize it. - -```js -const capitalizeEveryWord = str => str.replace(/\b[a-z]/g, char => char.toUpperCase()); -``` - +### capitalizeEveryWord + +Capitalizes the first letter of every word in a string. + +Use `String.replace()` to match the first character of each word and `String.toUpperCase()` to capitalize it. + +```js +const capitalizeEveryWord = str => str.replace(/\b[a-z]/g, char => char.toUpperCase()); +``` +
    Examples -```js -capitalizeEveryWord('hello world!'); // 'Hello World!' -``` +```js +capitalizeEveryWord('hello world!'); // 'Hello World!' +```

    [⬆ Back to top](#table-of-contents) -### countVowels - -Retuns `number` of vowels in provided string. - -Use a regular expression to count the number of vowels `(A, E, I, O, U)` in a `string`. - -```js -const countVowels = str => (str.match(/[aeiou]/gi) || []).length; -``` - +### countVowels + +Retuns `number` of vowels in provided string. + +Use a regular expression to count the number of vowels `(A, E, I, O, U)` in a `string`. + +```js +const countVowels = str => (str.match(/[aeiou]/gi) || []).length; +``` +
    Examples -```js -countVowels('foobar'); // 3 -countVowels('gym'); // 0 -``` +```js +countVowels('foobar'); // 3 +countVowels('gym'); // 0 +```

    [⬆ Back to top](#table-of-contents) -### escapeHTML - -Escapes a string for use in HTML. - -Use `String.replace()` with a regexp that matches the characters that need to be escaped, using a callback function to replace each character instance with its associated escaped character using a dictionary (object). - -```js -const escapeHTML = str => - str.replace( - /[&<>'"]/g, - tag => - ({ - '&': '&', - '<': '<', - '>': '>', - "'": ''', - '"': '"' - }[tag] || tag) - ); -``` - +### escapeHTML + +Escapes a string for use in HTML. + +Use `String.replace()` with a regexp that matches the characters that need to be escaped, using a callback function to replace each character instance with its associated escaped character using a dictionary (object). + +```js +const escapeHTML = str => + str.replace( + /[&<>'"]/g, + tag => + ({ + '&': '&', + '<': '<', + '>': '>', + "'": ''', + '"': '"' + }[tag] || tag) + ); +``` +
    Examples -```js -escapeHTML('Me & you'); // '<a href="#">Me & you</a>' -``` +```js +escapeHTML('Me & you'); // '<a href="#">Me & you</a>' +```

    [⬆ Back to top](#table-of-contents) -### escapeRegExp - -Escapes a string to use in a regular expression. - -Use `String.replace()` to escape special characters. - -```js -const escapeRegExp = str => str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); -``` - +### escapeRegExp + +Escapes a string to use in a regular expression. + +Use `String.replace()` to escape special characters. + +```js +const escapeRegExp = str => str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); +``` +
    Examples -```js -escapeRegExp('(test)'); // \\(test\\) -``` +```js +escapeRegExp('(test)'); // \\(test\\) +```

    [⬆ Back to top](#table-of-contents) -### fromCamelCase - -Converts a string from camelcase. - -Use `String.replace()` to remove underscores, hyphens, and spaces and convert words to camelcase. -Omit the second argument to use a default `separator` of `_`. - -```js -const fromCamelCase = (str, separator = '_') => - str - .replace(/([a-z\d])([A-Z])/g, '$1' + separator + '$2') - .replace(/([A-Z]+)([A-Z][a-z\d]+)/g, '$1' + separator + '$2') - .toLowerCase(); -``` - +### fromCamelCase + +Converts a string from camelcase. + +Use `String.replace()` to remove underscores, hyphens, and spaces and convert words to camelcase. +Omit the second argument to use a default `separator` of `_`. + +```js +const fromCamelCase = (str, separator = '_') => + str + .replace(/([a-z\d])([A-Z])/g, '$1' + separator + '$2') + .replace(/([A-Z]+)([A-Z][a-z\d]+)/g, '$1' + separator + '$2') + .toLowerCase(); +``` +
    Examples -```js -fromCamelCase('someDatabaseFieldName', ' '); // 'some database field name' -fromCamelCase('someLabelThatNeedsToBeCamelized', '-'); // 'some-label-that-needs-to-be-camelized' -fromCamelCase('someJavascriptProperty', '_'); // 'some_javascript_property' -``` +```js +fromCamelCase('someDatabaseFieldName', ' '); // 'some database field name' +fromCamelCase('someLabelThatNeedsToBeCamelized', '-'); // 'some-label-that-needs-to-be-camelized' +fromCamelCase('someJavascriptProperty', '_'); // 'some_javascript_property' +```

    [⬆ Back to top](#table-of-contents) -### isAbsoluteURL - -Returns `true` if the given string is an absolute URL, `false` otherwise. - -Use a regular expression to test if the string is an absolute URL. - -```js -const isAbsoluteURL = str => /^[a-z][a-z0-9+.-]*:/.test(str); -``` - +### isAbsoluteURL + +Returns `true` if the given string is an absolute URL, `false` otherwise. + +Use a regular expression to test if the string is an absolute URL. + +```js +const isAbsoluteURL = str => /^[a-z][a-z0-9+.-]*:/.test(str); +``` +
    Examples -```js -isAbsoluteURL('https://google.com'); // true -isAbsoluteURL('ftp://www.myserver.net'); // true -isAbsoluteURL('/foo/bar'); // false -``` +```js +isAbsoluteURL('https://google.com'); // true +isAbsoluteURL('ftp://www.myserver.net'); // true +isAbsoluteURL('/foo/bar'); // false +```

    [⬆ Back to top](#table-of-contents) -### isLowerCase - -Checks if a string is lower case. - -Convert the given string to lower case, using `String.toLowerCase()` and compare it to the original. - -```js -const isLowerCase = str => str === str.toLowerCase(); -``` - +### isLowerCase + +Checks if a string is lower case. + +Convert the given string to lower case, using `String.toLowerCase()` and compare it to the original. + +```js +const isLowerCase = str => str === str.toLowerCase(); +``` +
    Examples -```js -isLowerCase('abc'); // true -isLowerCase('a3@$'); // true -isLowerCase('Ab4'); // false -``` +```js +isLowerCase('abc'); // true +isLowerCase('a3@$'); // true +isLowerCase('Ab4'); // false +```

    [⬆ Back to top](#table-of-contents) -### isUpperCase - -Checks if a string is upper case. - -Convert the given string to upper case, using `String.toUpperCase()` and compare it to the original. - - -```js -const isUpperCase = str => str === str.toUpperCase(); -``` - +### isUpperCase + +Checks if a string is upper case. + +Convert the given string to upper case, using `String.toUpperCase()` and compare it to the original. + + +```js +const isUpperCase = str => str === str.toUpperCase(); +``` +
    Examples -```js -isUpperCase('ABC'); // true -isLowerCase('A3@$'); // true -isLowerCase('aB4'); // false -``` +```js +isUpperCase('ABC'); // true +isLowerCase('A3@$'); // true +isLowerCase('aB4'); // false +```

    [⬆ Back to top](#table-of-contents) -### mask - -Replaces all but the last `num` of characters with the specified mask character. - -Use `String.slice()` to grab the portion of the characters that need to be masked and use `String.replace()` with a regexp to replace every character with the mask character. -Concatenate the masked characters with the remaining unmasked portion of the string. -Omit the second argument, `num`, to keep a default of `4` characters unmasked. If `num` is negative, the unmasked characters will be at the start of the string. -Omit the third argument, `mask`, to use a default character of `'*'` for the mask. - -```js -const mask = (cc, num = 4, mask = '*') => - ('' + cc).slice(0, -num).replace(/./g, mask) + ('' + cc).slice(-num); -``` - +### mask + +Replaces all but the last `num` of characters with the specified mask character. + +Use `String.slice()` to grab the portion of the characters that need to be masked and use `String.replace()` with a regexp to replace every character with the mask character. +Concatenate the masked characters with the remaining unmasked portion of the string. +Omit the second argument, `num`, to keep a default of `4` characters unmasked. If `num` is negative, the unmasked characters will be at the start of the string. +Omit the third argument, `mask`, to use a default character of `'*'` for the mask. + +```js +const mask = (cc, num = 4, mask = '*') => + ('' + cc).slice(0, -num).replace(/./g, mask) + ('' + cc).slice(-num); +``` +
    Examples -```js -mask(1234567890); // '******7890' -mask(1234567890, 3); // '*******890' -mask(1234567890, -4, '$'); // '1234$$$$$$' -``` +```js +mask(1234567890); // '******7890' +mask(1234567890, 3); // '*******890' +mask(1234567890, -4, '$'); // '1234$$$$$$' +```

    [⬆ Back to top](#table-of-contents) -### palindrome - -Returns `true` if the given string is a palindrome, `false` otherwise. - -Convert string `String.toLowerCase()` and use `String.replace()` to remove non-alphanumeric characters from it. -Then, `String.split('')` into individual characters, `Array.reverse()`, `String.join('')` and compare to the original, unreversed string, after converting it `String.tolowerCase()`. - -```js -const palindrome = str => { - const s = str.toLowerCase().replace(/[\W_]/g, ''); - return ( - s === - s - .split('') - .reverse() - .join('') - ); -}; -``` - +### palindrome + +Returns `true` if the given string is a palindrome, `false` otherwise. + +Convert string `String.toLowerCase()` and use `String.replace()` to remove non-alphanumeric characters from it. +Then, `String.split('')` into individual characters, `Array.reverse()`, `String.join('')` and compare to the original, unreversed string, after converting it `String.tolowerCase()`. + +```js +const palindrome = str => { + const s = str.toLowerCase().replace(/[\W_]/g, ''); + return ( + s === + s + .split('') + .reverse() + .join('') + ); +}; +``` +
    Examples -```js -palindrome('taco cat'); // true -``` +```js +palindrome('taco cat'); // true +```

    [⬆ Back to top](#table-of-contents) -### pluralize - -Returns the singular or plural form of the word based on the input number. If the first argument is an `object`, it will use a closure by returning a function that can auto-pluralize words that don't simply end in `s` if the supplied dictionary contains the word. - -If `num` is either `-1` or `1`, return the singular form of the word. If `num` is any other number, return the plural form. Omit the third argument to use the default of the singular word + `s`, or supply a custom pluralized word when necessary. If the first argument is an `object`, utilize a closure by returning a function which can use the supplied dictionary to resolve the correct plural form of the word. - -```js -const pluralize = (val, word, plural = word + 's') => { - const _pluralize = (num, word, plural = word + 's') => - [1, -1].includes(Number(num)) ? word : plural; - if (typeof val === 'object') return (num, word) => _pluralize(num, word, val[word]); - return _pluralize(val, word, plural); -}; -``` - +### pluralize + +Returns the singular or plural form of the word based on the input number. If the first argument is an `object`, it will use a closure by returning a function that can auto-pluralize words that don't simply end in `s` if the supplied dictionary contains the word. + +If `num` is either `-1` or `1`, return the singular form of the word. If `num` is any other number, return the plural form. Omit the third argument to use the default of the singular word + `s`, or supply a custom pluralized word when necessary. If the first argument is an `object`, utilize a closure by returning a function which can use the supplied dictionary to resolve the correct plural form of the word. + +```js +const pluralize = (val, word, plural = word + 's') => { + const _pluralize = (num, word, plural = word + 's') => + [1, -1].includes(Number(num)) ? word : plural; + if (typeof val === 'object') return (num, word) => _pluralize(num, word, val[word]); + return _pluralize(val, word, plural); +}; +``` +
    Examples -```js -pluralize(0, 'apple'); // 'apples' -pluralize(1, 'apple'); // 'apple' -pluralize(2, 'apple'); // 'apples' -pluralize(2, 'person', 'people'); // 'people' - -const PLURALS = { - person: 'people', - radius: 'radii' -}; -const autoPluralize = pluralize(PLURALS); -autoPluralize(2, 'person'); // 'people' -``` +```js +pluralize(0, 'apple'); // 'apples' +pluralize(1, 'apple'); // 'apple' +pluralize(2, 'apple'); // 'apples' +pluralize(2, 'person', 'people'); // 'people' + +const PLURALS = { + person: 'people', + radius: 'radii' +}; +const autoPluralize = pluralize(PLURALS); +autoPluralize(2, 'person'); // 'people' +```

    [⬆ Back to top](#table-of-contents) -### reverseString - -Reverses a string. - -Use the spread operator (`...`) and `Array.reverse()` to reverse the order of the characters in the string. -Combine characters to get a string using `String.join('')`. - -```js -const reverseString = str => [...str].reverse().join(''); -``` - +### reverseString + +Reverses a string. + +Use the spread operator (`...`) and `Array.reverse()` to reverse the order of the characters in the string. +Combine characters to get a string using `String.join('')`. + +```js +const reverseString = str => [...str].reverse().join(''); +``` +
    Examples -```js -reverseString('foobar'); // 'raboof' -``` +```js +reverseString('foobar'); // 'raboof' +```

    [⬆ Back to top](#table-of-contents) -### sortCharactersInString - -Alphabetically sorts the characters in a string. - -Use the spread operator (`...`), `Array.sort()` and `String.localeCompare()` to sort the characters in `str`, recombine using `String.join('')`. - -```js -const sortCharactersInString = str => [...str].sort((a, b) => a.localeCompare(b)).join(''); -``` - +### sortCharactersInString + +Alphabetically sorts the characters in a string. + +Use the spread operator (`...`), `Array.sort()` and `String.localeCompare()` to sort the characters in `str`, recombine using `String.join('')`. + +```js +const sortCharactersInString = str => [...str].sort((a, b) => a.localeCompare(b)).join(''); +``` +
    Examples -```js -sortCharactersInString('cabbage'); // 'aabbceg' -``` +```js +sortCharactersInString('cabbage'); // 'aabbceg' +```

    [⬆ Back to top](#table-of-contents) -### splitLines - -Splits a multiline string into an array of lines. - -Use `String.split()` and a regular expression to match line breaks and create an array. - -```js -const splitLines = str => str.split(/\r?\n/); -``` - +### splitLines + +Splits a multiline string into an array of lines. + +Use `String.split()` and a regular expression to match line breaks and create an array. + +```js +const splitLines = str => str.split(/\r?\n/); +``` +
    Examples -```js -splitLines('This\nis a\nmultiline\nstring.\n'); // ['This', 'is a', 'multiline', 'string' , ''] -``` +```js +splitLines('This\nis a\nmultiline\nstring.\n'); // ['This', 'is a', 'multiline', 'string' , ''] +```

    [⬆ Back to top](#table-of-contents) -### toCamelCase - -Converts a string to camelcase. - -Break the string into words and combine them capitalizing the first letter of each word, using a regexp. - -```js -const toCamelCase = str => { - let s = - str && - str - .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) - .map(x => x.slice(0, 1).toUpperCase() + x.slice(1).toLowerCase()) - .join(''); - return s.slice(0, 1).toLowerCase() + s.slice(1); -}; -``` - +### toCamelCase + +Converts a string to camelcase. + +Break the string into words and combine them capitalizing the first letter of each word, using a regexp. + +```js +const toCamelCase = str => { + let s = + str && + str + .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) + .map(x => x.slice(0, 1).toUpperCase() + x.slice(1).toLowerCase()) + .join(''); + return s.slice(0, 1).toLowerCase() + s.slice(1); +}; +``` +
    Examples -```js -toCamelCase('some_database_field_name'); // 'someDatabaseFieldName' -toCamelCase('Some label that needs to be camelized'); // 'someLabelThatNeedsToBeCamelized' -toCamelCase('some-javascript-property'); // 'someJavascriptProperty' -toCamelCase('some-mixed_string with spaces_underscores-and-hyphens'); // 'someMixedStringWithSpacesUnderscoresAndHyphens' -``` +```js +toCamelCase('some_database_field_name'); // 'someDatabaseFieldName' +toCamelCase('Some label that needs to be camelized'); // 'someLabelThatNeedsToBeCamelized' +toCamelCase('some-javascript-property'); // 'someJavascriptProperty' +toCamelCase('some-mixed_string with spaces_underscores-and-hyphens'); // 'someMixedStringWithSpacesUnderscoresAndHyphens' +```

    [⬆ Back to top](#table-of-contents) -### toKebabCase - -Converts a string to kebab case. - -Break the string into words and combine them adding `-` as a separator, using a regexp. - -```js -const toKebabCase = str => - str && - str - .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) - .map(x => x.toLowerCase()) - .join('-'); -``` - +### toKebabCase + +Converts a string to kebab case. + +Break the string into words and combine them adding `-` as a separator, using a regexp. + +```js +const toKebabCase = str => + str && + str + .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) + .map(x => x.toLowerCase()) + .join('-'); +``` +
    Examples -```js -toKebabCase('camelCase'); // 'camel-case' -toKebabCase('some text'); // 'some-text' -toKebabCase('some-mixed_string With spaces_underscores-and-hyphens'); // 'some-mixed-string-with-spaces-underscores-and-hyphens' -toKebabCase('AllThe-small Things'); // "all-the-small-things" -toKebabCase('IAmListeningToFMWhileLoadingDifferentURLOnMyBrowserAndAlsoEditingSomeXMLAndHTML'); // "i-am-listening-to-fm-while-loading-different-url-on-my-browser-and-also-editing-xml-and-html" -``` +```js +toKebabCase('camelCase'); // 'camel-case' +toKebabCase('some text'); // 'some-text' +toKebabCase('some-mixed_string With spaces_underscores-and-hyphens'); // 'some-mixed-string-with-spaces-underscores-and-hyphens' +toKebabCase('AllThe-small Things'); // "all-the-small-things" +toKebabCase('IAmListeningToFMWhileLoadingDifferentURLOnMyBrowserAndAlsoEditingSomeXMLAndHTML'); // "i-am-listening-to-fm-while-loading-different-url-on-my-browser-and-also-editing-xml-and-html" +```

    [⬆ Back to top](#table-of-contents) -### toSnakeCase - -Converts a string to snake case. - -Break the string into words and combine them adding `_` as a separator, using a regexp. - -```js -const toSnakeCase = str => - str && - str - .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) - .map(x => x.toLowerCase()) - .join('_'); -``` - +### toSnakeCase + +Converts a string to snake case. + +Break the string into words and combine them adding `_` as a separator, using a regexp. + +```js +const toSnakeCase = str => + str && + str + .match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g) + .map(x => x.toLowerCase()) + .join('_'); +``` +
    Examples -```js -toSnakeCase('camelCase'); // 'camel_case' -toSnakeCase('some text'); // 'some_text' -toSnakeCase('some-mixed_string With spaces_underscores-and-hyphens'); // 'some_mixed_string_with_spaces_underscores_and_hyphens' -toSnakeCase('AllThe-small Things'); // "all_the_smal_things" -toSnakeCase('IAmListeningToFMWhileLoadingDifferentURLOnMyBrowserAndAlsoEditingSomeXMLAndHTML'); // "i_am_listening_to_fm_while_loading_different_url_on_my_browser_and_also_editing_some_xml_and_html" -``` +```js +toSnakeCase('camelCase'); // 'camel_case' +toSnakeCase('some text'); // 'some_text' +toSnakeCase('some-mixed_string With spaces_underscores-and-hyphens'); // 'some_mixed_string_with_spaces_underscores_and_hyphens' +toSnakeCase('AllThe-small Things'); // "all_the_smal_things" +toSnakeCase('IAmListeningToFMWhileLoadingDifferentURLOnMyBrowserAndAlsoEditingSomeXMLAndHTML'); // "i_am_listening_to_fm_while_loading_different_url_on_my_browser_and_also_editing_some_xml_and_html" +```

    [⬆ Back to top](#table-of-contents) -### truncateString - -Truncates a string up to a specified length. - -Determine if the string's `length` is greater than `num`. -Return the string truncated to the desired length, with `'...'` appended to the end or the original string. - -```js -const truncateString = (str, num) => - str.length > num ? str.slice(0, num > 3 ? num - 3 : num) + '...' : str; -``` - +### truncateString + +Truncates a string up to a specified length. + +Determine if the string's `length` is greater than `num`. +Return the string truncated to the desired length, with `'...'` appended to the end or the original string. + +```js +const truncateString = (str, num) => + str.length > num ? str.slice(0, num > 3 ? num - 3 : num) + '...' : str; +``` +
    Examples -```js -truncateString('boomerang', 7); // 'boom...' -``` +```js +truncateString('boomerang', 7); // 'boom...' +```

    [⬆ Back to top](#table-of-contents) -### unescapeHTML - -Unescapes escaped HTML characters. - -Use `String.replace()` with a regex that matches the characters that need to be unescaped, using a callback function to replace each escaped character instance with its associated unescaped character using a dictionary (object). - -```js -const unescapeHTML = str => - str.replace( - /&|<|>|'|"/g, - tag => - ({ - '&': '&', - '<': '<', - '>': '>', - ''': "'", - '"': '"' - }[tag] || tag) - ); -``` - +### unescapeHTML + +Unescapes escaped HTML characters. + +Use `String.replace()` with a regex that matches the characters that need to be unescaped, using a callback function to replace each escaped character instance with its associated unescaped character using a dictionary (object). + +```js +const unescapeHTML = str => + str.replace( + /&|<|>|'|"/g, + tag => + ({ + '&': '&', + '<': '<', + '>': '>', + ''': "'", + '"': '"' + }[tag] || tag) + ); +``` +
    Examples -```js -unescapeHTML('<a href="#">Me & you</a>'); // 'Me & you' -``` +```js +unescapeHTML('<a href="#">Me & you</a>'); // 'Me & you' +```

    [⬆ Back to top](#table-of-contents) -### words - -Converts a given string into an array of words. - -Use `String.split()` with a supplied pattern (defaults to non-alpha as a regexp) to convert to an array of strings. Use `Array.filter()` to remove any empty strings. -Omit the second argument to use the default regexp. - -```js -const words = (str, pattern = /[^a-zA-Z-]+/) => str.split(pattern).filter(Boolean); -``` - +### words + +Converts a given string into an array of words. + +Use `String.split()` with a supplied pattern (defaults to non-alpha as a regexp) to convert to an array of strings. Use `Array.filter()` to remove any empty strings. +Omit the second argument to use the default regexp. + +```js +const words = (str, pattern = /[^a-zA-Z-]+/) => str.split(pattern).filter(Boolean); +``` +
    Examples -```js -words('I love javaScript!!'); // ["I", "love", "javaScript"] -words('python, javaScript & coffee'); // ["python", "javaScript", "coffee"] -``` +```js +words('I love javaScript!!'); // ["I", "love", "javaScript"] +words('python, javaScript & coffee'); // ["python", "javaScript", "coffee"] +```
    @@ -4530,301 +4530,301 @@ words('python, javaScript & coffee'); // ["python", "javaScript", "coffee"] --- ## Type -### getType - -Returns the native type of a value. - -Returns lowercased constructor name of value, `"undefined"` or `"null"` if value is `undefined` or `null`. - -```js -const getType = v => - v === undefined ? 'undefined' : v === null ? 'null' : v.constructor.name.toLowerCase(); -``` - +### getType + +Returns the native type of a value. + +Returns lowercased constructor name of value, `"undefined"` or `"null"` if value is `undefined` or `null`. + +```js +const getType = v => + v === undefined ? 'undefined' : v === null ? 'null' : v.constructor.name.toLowerCase(); +``` +
    Examples -```js -getType(new Set([1, 2, 3])); // 'Set' -``` +```js +getType(new Set([1, 2, 3])); // 'Set' +```

    [⬆ Back to top](#table-of-contents) -### isArray - -Checks if the given argument is an array. - -Use `Array.isArray()` to check if a value is classified as an array. - -```js -const isArray = val => Array.isArray(val); -``` - +### isArray + +Checks if the given argument is an array. + +Use `Array.isArray()` to check if a value is classified as an array. + +```js +const isArray = val => Array.isArray(val); +``` +
    Examples -```js -isArray([1]); // true -``` +```js +isArray([1]); // true +```

    [⬆ Back to top](#table-of-contents) -### isArrayLike - -Checks if the provided argument is array-like (i.e. is iterable). - -Use the spread operator (`...`) to check if the provided argument is iterable inside a `try... catch` block and the comma operator (`,`) to return the appropriate value. - -```js -const isArrayLike = val => { - try { - return [...val], true; - } catch (e) { - return false; - } -}; -``` - +### isArrayLike + +Checks if the provided argument is array-like (i.e. is iterable). + +Use the spread operator (`...`) to check if the provided argument is iterable inside a `try... catch` block and the comma operator (`,`) to return the appropriate value. + +```js +const isArrayLike = val => { + try { + return [...val], true; + } catch (e) { + return false; + } +}; +``` +
    Examples -```js -isArrayLike(document.querySelectorAll('.className')); // true -isArrayLike('abc'); // true -isArrayLike(null); // false -``` +```js +isArrayLike(document.querySelectorAll('.className')); // true +isArrayLike('abc'); // true +isArrayLike(null); // false +```

    [⬆ Back to top](#table-of-contents) -### isBoolean - -Checks if the given argument is a native boolean element. - -Use `typeof` to check if a value is classified as a boolean primitive. - -```js -const isBoolean = val => typeof val === 'boolean'; -``` - +### isBoolean + +Checks if the given argument is a native boolean element. + +Use `typeof` to check if a value is classified as a boolean primitive. + +```js +const isBoolean = val => typeof val === 'boolean'; +``` +
    Examples -```js -isBoolean(null); // false -isBoolean(false); // true -``` +```js +isBoolean(null); // false +isBoolean(false); // true +```

    [⬆ Back to top](#table-of-contents) -### isFunction - -Checks if the given argument is a function. - -Use `typeof` to check if a value is classified as a function primitive. - -```js -const isFunction = val => typeof val === 'function'; -``` - +### isFunction + +Checks if the given argument is a function. + +Use `typeof` to check if a value is classified as a function primitive. + +```js +const isFunction = val => typeof val === 'function'; +``` +
    Examples -```js -isFunction('x'); // false -isFunction(x => x); // true -``` +```js +isFunction('x'); // false +isFunction(x => x); // true +```

    [⬆ Back to top](#table-of-contents) -### isNull - -Returns `true` if the specified value is `null`, `false` otherwise. - -Use the strict equality operator to check if the value and of `val` are equal to `null`. - -```js -const isNull = val => val === null; -``` - +### isNull + +Returns `true` if the specified value is `null`, `false` otherwise. + +Use the strict equality operator to check if the value and of `val` are equal to `null`. + +```js +const isNull = val => val === null; +``` +
    Examples -```js -isNull(null); // true -``` +```js +isNull(null); // true +```

    [⬆ Back to top](#table-of-contents) -### isNumber - -Checks if the given argument is a number. - -Use `typeof` to check if a value is classified as a number primitive. - -```js -const isNumber = val => typeof val === 'number'; -``` - +### isNumber + +Checks if the given argument is a number. + +Use `typeof` to check if a value is classified as a number primitive. + +```js +const isNumber = val => typeof val === 'number'; +``` +
    Examples -```js -isNumber('1'); // false -isNumber(1); // true -``` +```js +isNumber('1'); // false +isNumber(1); // true +```

    [⬆ Back to top](#table-of-contents) -### isPrimitive - -Returns a boolean determining if the supplied value is primitive or not. - -Use `Array.includes()` on an array of type strings which are not primitive, -supplying the type using `typeof`. -Since `typeof null` evaluates to `'object'`, it needs to be directly compared. - -```js -const isPrimitive = val => !['object', 'function'].includes(typeof val) || val === null; -``` - +### isPrimitive + +Returns a boolean determining if the supplied value is primitive or not. + +Use `Array.includes()` on an array of type strings which are not primitive, +supplying the type using `typeof`. +Since `typeof null` evaluates to `'object'`, it needs to be directly compared. + +```js +const isPrimitive = val => !['object', 'function'].includes(typeof val) || val === null; +``` +
    Examples -```js -isPrimitive(null); // true -isPrimitive(50); // true -isPrimitive('Hello!'); // true -isPrimitive(false); // true -isPrimitive(Symbol()); // true -isPrimitive([]); // false -``` +```js +isPrimitive(null); // true +isPrimitive(50); // true +isPrimitive('Hello!'); // true +isPrimitive(false); // true +isPrimitive(Symbol()); // true +isPrimitive([]); // false +```

    [⬆ Back to top](#table-of-contents) -### isPromiseLike - -Returns `true` if an object looks like a [`Promise`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise), `false` otherwise. - -Check if the object is not `null`, its `typeof` matches either `object` or `function` and if it has a `.then` property, which is also a `function`. - -```js -const isPromiseLike = obj => - obj !== null && - (typeof obj === 'object' || typeof obj === 'function') && - typeof obj.then === 'function'; -``` - +### isPromiseLike + +Returns `true` if an object looks like a [`Promise`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise), `false` otherwise. + +Check if the object is not `null`, its `typeof` matches either `object` or `function` and if it has a `.then` property, which is also a `function`. + +```js +const isPromiseLike = obj => + obj !== null && + (typeof obj === 'object' || typeof obj === 'function') && + typeof obj.then === 'function'; +``` +
    Examples -```js -isPromiseLike({ - then: function() { - return ''; - } -}); // true -isPromiseLike(null); // false -isPromiseLike({}); // false -``` +```js +isPromiseLike({ + then: function() { + return ''; + } +}); // true +isPromiseLike(null); // false +isPromiseLike({}); // false +```

    [⬆ Back to top](#table-of-contents) -### isString - -Checks if the given argument is a string. - -Use `typeof` to check if a value is classified as a string primitive. - -```js -const isString = val => typeof val === 'string'; -``` - +### isString + +Checks if the given argument is a string. + +Use `typeof` to check if a value is classified as a string primitive. + +```js +const isString = val => typeof val === 'string'; +``` +
    Examples -```js -isString('10'); // true -``` +```js +isString('10'); // true +```

    [⬆ Back to top](#table-of-contents) -### isSymbol - -Checks if the given argument is a symbol. - -Use `typeof` to check if a value is classified as a symbol primitive. - -```js -const isSymbol = val => typeof val === 'symbol'; -``` - +### isSymbol + +Checks if the given argument is a symbol. + +Use `typeof` to check if a value is classified as a symbol primitive. + +```js +const isSymbol = val => typeof val === 'symbol'; +``` +
    Examples -```js -isSymbol(Symbol('x')); // true -``` +```js +isSymbol(Symbol('x')); // true +```

    [⬆ Back to top](#table-of-contents) -### isValidJSON - -Checks if the provided argument is a valid JSON. - -Use `JSON.parse()` and a `try... catch` block to check if the provided argument is a valid JSON. - -```js -const isValidJSON = obj => { - try { - JSON.parse(obj); - return true; - } catch (e) { - return false; - } -}; -``` - +### isValidJSON + +Checks if the provided argument is a valid JSON. + +Use `JSON.parse()` and a `try... catch` block to check if the provided argument is a valid JSON. + +```js +const isValidJSON = obj => { + try { + JSON.parse(obj); + return true; + } catch (e) { + return false; + } +}; +``` +
    Examples -```js -isValidJSON('{"name":"Adam","age":20}'); // true -isValidJSON('{"name":"Adam",age:"20"}'); // false -isValidJSON(null); // true -``` +```js +isValidJSON('{"name":"Adam","age":20}'); // true +isValidJSON('{"name":"Adam",age:"20"}'); // false +isValidJSON(null); // true +```
    @@ -4833,124 +4833,124 @@ isValidJSON(null); // true --- ## 🔧 Utility -### cloneRegExp - -Clones a regular expression. - -Use `new RegExp()`, `RegExp.source` and `RegExp.flags` to clone the given regular expression. - -```js -const cloneRegExp = regExp => new RegExp(regExp.source, regExp.flags); -``` - +### cloneRegExp + +Clones a regular expression. + +Use `new RegExp()`, `RegExp.source` and `RegExp.flags` to clone the given regular expression. + +```js +const cloneRegExp = regExp => new RegExp(regExp.source, regExp.flags); +``` +
    Examples -```js -const regExp = /lorem ipsum/gi; -const regExp2 = cloneRegExp(regExp); // /lorem ipsum/gi -``` +```js +const regExp = /lorem ipsum/gi; +const regExp2 = cloneRegExp(regExp); // /lorem ipsum/gi +```

    [⬆ Back to top](#table-of-contents) -### coalesce - -Returns the first non-null/undefined argument. - -Use `Array.find()` to return the first non `null`/`undefined` argument. - -```js -const coalesce = (...args) => args.find(_ => ![undefined, null].includes(_)); -``` - +### coalesce + +Returns the first non-null/undefined argument. + +Use `Array.find()` to return the first non `null`/`undefined` argument. + +```js +const coalesce = (...args) => args.find(_ => ![undefined, null].includes(_)); +``` +
    Examples -```js -coalesce(null, undefined, '', NaN, 'Waldo'); // "" -``` +```js +coalesce(null, undefined, '', NaN, 'Waldo'); // "" +```

    [⬆ Back to top](#table-of-contents) -### coalesceFactory - -Returns a customized coalesce function that returns the first argument that returns `true` from the provided argument validation function. - -Use `Array.find()` to return the first argument that returns `true` from the provided argument validation function. - -```js -const coalesceFactory = valid => (...args) => args.find(valid); -``` - +### coalesceFactory + +Returns a customized coalesce function that returns the first argument that returns `true` from the provided argument validation function. + +Use `Array.find()` to return the first argument that returns `true` from the provided argument validation function. + +```js +const coalesceFactory = valid => (...args) => args.find(valid); +``` +
    Examples -```js -const customCoalesce = coalesceFactory(_ => ![null, undefined, '', NaN].includes(_)); -customCoalesce(undefined, null, NaN, '', 'Waldo'); // "Waldo" -``` +```js +const customCoalesce = coalesceFactory(_ => ![null, undefined, '', NaN].includes(_)); +customCoalesce(undefined, null, NaN, '', 'Waldo'); // "Waldo" +```

    [⬆ Back to top](#table-of-contents) -### extendHex - -Extends a 3-digit color code to a 6-digit color code. - -Use `Array.map()`, `String.split()` and `Array.join()` to join the mapped array for converting a 3-digit RGB notated hexadecimal color-code to the 6-digit form. -`Array.slice()` is used to remove `#` from string start since it's added once. - -```js -const extendHex = shortHex => - '#' + - shortHex - .slice(shortHex.startsWith('#') ? 1 : 0) - .split('') - .map(x => x + x) - .join(''); -``` - +### extendHex + +Extends a 3-digit color code to a 6-digit color code. + +Use `Array.map()`, `String.split()` and `Array.join()` to join the mapped array for converting a 3-digit RGB notated hexadecimal color-code to the 6-digit form. +`Array.slice()` is used to remove `#` from string start since it's added once. + +```js +const extendHex = shortHex => + '#' + + shortHex + .slice(shortHex.startsWith('#') ? 1 : 0) + .split('') + .map(x => x + x) + .join(''); +``` +
    Examples -```js -extendHex('#03f'); // '#0033ff' -extendHex('05a'); // '#0055aa' -``` +```js +extendHex('#03f'); // '#0033ff' +extendHex('05a'); // '#0055aa' +```

    [⬆ Back to top](#table-of-contents) -### getURLParameters - -Returns an object containing the parameters of the current URL. - -Use `String.match()` with an appropriate regular expression to get all key-value pairs, `Array.reduce()` to map and combine them into a single object. -Pass `location.search` as the argument to apply to the current `url`. - -```js -const getURLParameters = url => - url - .match(/([^?=&]+)(=([^&]*))/g) - .reduce((a, v) => ((a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1)), a), {}); -``` - +### getURLParameters + +Returns an object containing the parameters of the current URL. + +Use `String.match()` with an appropriate regular expression to get all key-value pairs, `Array.reduce()` to map and combine them into a single object. +Pass `location.search` as the argument to apply to the current `url`. + +```js +const getURLParameters = url => + url + .match(/([^?=&]+)(=([^&]*))/g) + .reduce((a, v) => ((a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1)), a), {}); +``` +
    Examples -```js -getURLParameters('http://url.com/page?name=Adam&surname=Smith'); // {name: 'Adam', surname: 'Smith'} -``` +```js +getURLParameters('http://url.com/page?name=Adam&surname=Smith'); // {name: 'Adam', surname: 'Smith'} +```
    @@ -4999,226 +4999,226 @@ hexToRGB('#fff'); // 'rgb(255, 255, 255)'
    [⬆ Back to top](#table-of-contents) -### prettyBytes - -Converts a number in bytes to a human-readable string. - -Use an array dictionary of units to be accessed based on the exponent. -Use `Number.toPrecision()` to truncate the number to a certain number of digits. -Return the prettified string by building it up, taking into account the supplied options and whether it is negative or not. -Omit the second argument, `precision`, to use a default precision of `3` digits. -Omit the third argument, `addSpace`, to add space between the number and unit by default. - -```js -const prettyBytes = (num, precision = 3, addSpace = true) => { - const UNITS = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB']; - if (Math.abs(num) < 1) return num + (addSpace ? ' ' : '') + UNITS[0]; - const exponent = Math.min(Math.floor(Math.log10(num < 0 ? -num : num) / 3), UNITS.length - 1); - const n = Number(((num < 0 ? -num : num) / 1000 ** exponent).toPrecision(precision)); - return (num < 0 ? '-' : '') + n + (addSpace ? ' ' : '') + UNITS[exponent]; -}; -``` - +### prettyBytes + +Converts a number in bytes to a human-readable string. + +Use an array dictionary of units to be accessed based on the exponent. +Use `Number.toPrecision()` to truncate the number to a certain number of digits. +Return the prettified string by building it up, taking into account the supplied options and whether it is negative or not. +Omit the second argument, `precision`, to use a default precision of `3` digits. +Omit the third argument, `addSpace`, to add space between the number and unit by default. + +```js +const prettyBytes = (num, precision = 3, addSpace = true) => { + const UNITS = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB']; + if (Math.abs(num) < 1) return num + (addSpace ? ' ' : '') + UNITS[0]; + const exponent = Math.min(Math.floor(Math.log10(num < 0 ? -num : num) / 3), UNITS.length - 1); + const n = Number(((num < 0 ? -num : num) / 1000 ** exponent).toPrecision(precision)); + return (num < 0 ? '-' : '') + n + (addSpace ? ' ' : '') + UNITS[exponent]; +}; +``` +
    Examples -```js -prettyBytes(1000); // 1 KB -prettyBytes(-27145424323.5821, 5); // -27.145 GB -prettyBytes(123456789, 3, false); // 123MB -``` +```js +prettyBytes(1000); // 1 KB +prettyBytes(-27145424323.5821, 5); // -27.145 GB +prettyBytes(123456789, 3, false); // 123MB +```

    [⬆ Back to top](#table-of-contents) -### randomHexColorCode - -Generates a random hexadecimal color code. - -Use `Math.random` to generate a random 24-bit(6x4bits) hexadecimal number. Use bit shifting and then convert it to an hexadecimal String using `toString(16)`. - -```js -const randomHexColorCode = () => { - let n = ((Math.random() * 0xfffff) | 0).toString(16); - return '#' + (n.length !== 6 ? ((Math.random() * 0xf) | 0).toString(16) + n : n); -}; -``` - +### randomHexColorCode + +Generates a random hexadecimal color code. + +Use `Math.random` to generate a random 24-bit(6x4bits) hexadecimal number. Use bit shifting and then convert it to an hexadecimal String using `toString(16)`. + +```js +const randomHexColorCode = () => { + let n = ((Math.random() * 0xfffff) | 0).toString(16); + return '#' + (n.length !== 6 ? ((Math.random() * 0xf) | 0).toString(16) + n : n); +}; +``` +
    Examples -```js -randomHexColorCode(); // "#e34155" -``` +```js +randomHexColorCode(); // "#e34155" +```

    [⬆ Back to top](#table-of-contents) -### RGBToHex - -Converts the values of RGB components to a color code. - -Convert given RGB parameters to hexadecimal string using bitwise left-shift operator (`<<`) and `toString(16)`, then `String.padStart(6,'0')` to get a 6-digit hexadecimal value. - -```js -const RGBToHex = (r, g, b) => ((r << 16) + (g << 8) + b).toString(16).padStart(6, '0'); -``` - +### RGBToHex + +Converts the values of RGB components to a color code. + +Convert given RGB parameters to hexadecimal string using bitwise left-shift operator (`<<`) and `toString(16)`, then `String.padStart(6,'0')` to get a 6-digit hexadecimal value. + +```js +const RGBToHex = (r, g, b) => ((r << 16) + (g << 8) + b).toString(16).padStart(6, '0'); +``` +
    Examples -```js -RGBToHex(255, 165, 1); // 'ffa501' -``` +```js +RGBToHex(255, 165, 1); // 'ffa501' +```

    [⬆ Back to top](#table-of-contents) -### timeTaken - -Measures the time taken by a function to execute. - -Use `console.time()` and `console.timeEnd()` to measure the difference between the start and end times to determine how long the callback took to execute. - -```js -const timeTaken = callback => { - console.time('timeTaken'); - const r = callback(); - console.timeEnd('timeTaken'); - return r; -}; -``` - +### timeTaken + +Measures the time taken by a function to execute. + +Use `console.time()` and `console.timeEnd()` to measure the difference between the start and end times to determine how long the callback took to execute. + +```js +const timeTaken = callback => { + console.time('timeTaken'); + const r = callback(); + console.timeEnd('timeTaken'); + return r; +}; +``` +
    Examples -```js -timeTaken(() => Math.pow(2, 10)); // 1024, (logged): timeTaken: 0.02099609375ms -``` +```js +timeTaken(() => Math.pow(2, 10)); // 1024, (logged): timeTaken: 0.02099609375ms +```

    [⬆ Back to top](#table-of-contents) -### toDecimalMark - -Use `toLocaleString()` to convert a float-point arithmetic to the [Decimal mark](https://en.wikipedia.org/wiki/Decimal_mark) form. It makes a comma separated string from a number. - - ```js -const toDecimalMark = num => num.toLocaleString('en-US'); -``` - +### toDecimalMark + +Use `toLocaleString()` to convert a float-point arithmetic to the [Decimal mark](https://en.wikipedia.org/wiki/Decimal_mark) form. It makes a comma separated string from a number. + + ```js +const toDecimalMark = num => num.toLocaleString('en-US'); +``` +
    Examples -```js -toDecimalMark(12305030388.9087); // "12,305,030,388.9087" -``` +```js +toDecimalMark(12305030388.9087); // "12,305,030,388.9087" +```

    [⬆ Back to top](#table-of-contents) -### toOrdinalSuffix - -Adds an ordinal suffix to a number. - -Use the modulo operator (`%`) to find values of single and tens digits. -Find which ordinal pattern digits match. -If digit is found in teens pattern, use teens ordinal. - -```js -const toOrdinalSuffix = num => { - const int = parseInt(num), - digits = [int % 10, int % 100], - ordinals = ['st', 'nd', 'rd', 'th'], - oPattern = [1, 2, 3, 4], - tPattern = [11, 12, 13, 14, 15, 16, 17, 18, 19]; - return oPattern.includes(digits[0]) && !tPattern.includes(digits[1]) - ? int + ordinals[digits[0] - 1] - : int + ordinals[3]; -}; -``` - +### toOrdinalSuffix + +Adds an ordinal suffix to a number. + +Use the modulo operator (`%`) to find values of single and tens digits. +Find which ordinal pattern digits match. +If digit is found in teens pattern, use teens ordinal. + +```js +const toOrdinalSuffix = num => { + const int = parseInt(num), + digits = [int % 10, int % 100], + ordinals = ['st', 'nd', 'rd', 'th'], + oPattern = [1, 2, 3, 4], + tPattern = [11, 12, 13, 14, 15, 16, 17, 18, 19]; + return oPattern.includes(digits[0]) && !tPattern.includes(digits[1]) + ? int + ordinals[digits[0] - 1] + : int + ordinals[3]; +}; +``` +
    Examples -```js -toOrdinalSuffix('123'); // "123rd" -``` +```js +toOrdinalSuffix('123'); // "123rd" +```

    [⬆ Back to top](#table-of-contents) -### validateNumber - -Returns `true` if the given value is a number, `false` otherwise. - -Use `!isNaN()` in combination with `parseFloat()` to check if the argument is a number. -Use `isFinite()` to check if the number is finite. -Use `Number()` to check if the coercion holds. - -```js -const validateNumber = n => !isNaN(parseFloat(n)) && isFinite(n) && Number(n) == n; -``` - +### validateNumber + +Returns `true` if the given value is a number, `false` otherwise. + +Use `!isNaN()` in combination with `parseFloat()` to check if the argument is a number. +Use `isFinite()` to check if the number is finite. +Use `Number()` to check if the coercion holds. + +```js +const validateNumber = n => !isNaN(parseFloat(n)) && isFinite(n) && Number(n) == n; +``` +
    Examples -```js -validateNumber('10'); // true -``` +```js +validateNumber('10'); // true +```

    [⬆ Back to top](#table-of-contents) -### yesNo - -Returns `true` if the string is `y`/`yes` or `false` if the string is `n`/`no`. - -Use `RegExp.test()` to check if the string evaluates to `y/yes` or `n/no`. -Omit the second argument, `def` to set the default answer as `no`. - -```js -const yesNo = (val, def = false) => - /^(y|yes)$/i.test(val) ? true : /^(n|no)$/i.test(val) ? false : def; -``` - +### yesNo + +Returns `true` if the string is `y`/`yes` or `false` if the string is `n`/`no`. + +Use `RegExp.test()` to check if the string evaluates to `y/yes` or `n/no`. +Omit the second argument, `def` to set the default answer as `no`. + +```js +const yesNo = (val, def = false) => + /^(y|yes)$/i.test(val) ? true : /^(n|no)$/i.test(val) ? false : def; +``` +
    Examples -```js -yesNo('Y'); // true -yesNo('yes'); // true -yesNo('No'); // false -yesNo('Foo', true); // true -``` +```js +yesNo('Y'); // true +yesNo('yes'); // true +yesNo('No'); // false +yesNo('Foo', true); // true +```

    [⬆ Back to top](#table-of-contents) -## Collaborators - -| [](https://github.com/Chalarangelo)
    [Angelos Chalaris](https://github.com/Chalarangelo) | [](https://github.com/Pl4gue)
    [David Wu](https://github.com/Pl4gue) | [](https://github.com/fejes713)
    [Stefan Feješ](https://github.com/fejes713) | [](https://github.com/kingdavidmartins)
    [King David Martins](https://github.com/iamsoorena) | [](https://github.com/iamsoorena)
    [Soorena Soleimani](https://github.com/iamsoorena) | -| --- | --- | --- | --- | --- | -| [](https://github.com/elderhsouza)
    [Elder Henrique Souza](https://github.com/elderhsouza) | [](https://github.com/skatcat31)
    [Robert Mennell](https://github.com/skatcat31) | [](https://github.com/atomiks)
    [atomiks](https://github.com/atomiks) | - - -## Credits - -*Icons made by [Smashicons](https://www.flaticon.com/authors/smashicons) from [www.flaticon.com](https://www.flaticon.com/) is licensed by [CC 3.0 BY](http://creativecommons.org/licenses/by/3.0/).* +## Collaborators + +| [](https://github.com/Chalarangelo)
    [Angelos Chalaris](https://github.com/Chalarangelo) | [](https://github.com/Pl4gue)
    [David Wu](https://github.com/Pl4gue) | [](https://github.com/fejes713)
    [Stefan Feješ](https://github.com/fejes713) | [](https://github.com/kingdavidmartins)
    [King David Martins](https://github.com/iamsoorena) | [](https://github.com/iamsoorena)
    [Soorena Soleimani](https://github.com/iamsoorena) | +| --- | --- | --- | --- | --- | +| [](https://github.com/elderhsouza)
    [Elder Henrique Souza](https://github.com/elderhsouza) | [](https://github.com/skatcat31)
    [Robert Mennell](https://github.com/skatcat31) | [](https://github.com/atomiks)
    [atomiks](https://github.com/atomiks) | + + +## Credits + +*Icons made by [Smashicons](https://www.flaticon.com/authors/smashicons) from [www.flaticon.com](https://www.flaticon.com/) is licensed by [CC 3.0 BY](http://creativecommons.org/licenses/by/3.0/).* From 0e828a0f8566430cf94b33f765886508caadba2e Mon Sep 17 00:00:00 2001 From: Angelos Chalaris Date: Mon, 8 Jan 2018 21:58:35 +0200 Subject: [PATCH 7/7] Update longestItem.md --- snippets/longestItem.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/snippets/longestItem.md b/snippets/longestItem.md index 31afe5bb9..db4371ca8 100644 --- a/snippets/longestItem.md +++ b/snippets/longestItem.md @@ -1,8 +1,8 @@ ### longestItem -Takes any iterable object or object with a `length` property and returns the longest one. +Takes any number of iterable objects or objects with a `length` property and returns the longest one. -The function sorts all arguments by their `length` and returns the first (longest) one. +Use `Array.sort()` to sort all arguments by `length`, return the first (longest) one. ```js const longestItem = (...vals) => [...vals].sort((a, b) => b.length - a.length)[0];