From 4a1309578be43c6db87f50a13dba20f6d6e63f47 Mon Sep 17 00:00:00 2001 From: Angelos Chalaris Date: Thu, 28 Dec 2017 12:13:34 +0200 Subject: [PATCH] Update builder --- README.md | 5322 ++++++++++++++++++++------------------- scripts/build-script.js | 2 +- 2 files changed, 2732 insertions(+), 2592 deletions(-) diff --git a/README.md b/README.md index ca6bd2f13..1ec944b1f 100644 --- a/README.md +++ b/README.md @@ -1,19 +1,19 @@ -![Logo](/logo.png) +![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) [![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) + +> 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 Alfred 3, using [this file](https://github.com/lslvxy/30-seconds-of-code-alfredsnippets). + +## Table of Contents -# 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) [![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) - -> 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 Alfred 3, using [this file](https://github.com/lslvxy/30-seconds-of-code-alfredsnippets). - -## Table of Contents - -### Adapter +### Adapter * [`call`](#call) * [`collectInto`](#collectinto) * [`flip`](#flip) @@ -21,7 +21,7 @@ * [`promisify`](#promisify) * [`spreadOver`](#spreadover) -### Array +### Array * [`arrayGcd`](#arraygcd) * [`arrayLcm`](#arraylcm) * [`arrayMax`](#arraymax) @@ -66,7 +66,7 @@ * [`zip`](#zip) * [`zipObject`](#zipobject) -### Browser +### Browser * [`arrayToHtmlList`](#arraytohtmllist) * [`bottomVisible`](#bottomvisible) * [`currentURL`](#currenturl) @@ -78,13 +78,13 @@ * [`redirect`](#redirect) * [`scrollToTop`](#scrolltotop) -### Date +### Date * [`getDaysDiffBetweenDates`](#getdaysdiffbetweendates) * [`JSONToDate`](#jsontodate) * [`toEnglishDate`](#toenglishdate) * [`tomorrow`](#tomorrow) -### Function +### Function * [`chainAsync`](#chainasync) * [`compose`](#compose) * [`curry`](#curry) @@ -92,10 +92,10 @@ * [`runPromisesInSeries`](#runpromisesinseries) * [`sleep`](#sleep) -### Logic +### Logic * [`negate`](#negate) -### Math +### Math * [`arrayAverage`](#arrayaverage) * [`arraySum`](#arraysum) * [`clampNumber`](#clampnumber) @@ -124,14 +124,14 @@ * [`round`](#round) * [`standardDeviation`](#standarddeviation) -### Media +### Media * [`speechSynthesis`](#speechsynthesis) -### Node +### Node * [`JSONToFile`](#jsontofile) * [`readFileLines`](#readfilelines) -### Object +### Object * [`cleanObj`](#cleanobj) * [`objectFromPairs`](#objectfrompairs) * [`objectToPairs`](#objecttopairs) @@ -140,7 +140,7 @@ * [`shallowClone`](#shallowclone) * [`truthCheckCollection`](#truthcheckcollection) -### String +### String * [`anagrams`](#anagrams) * [`capitalize`](#capitalize) * [`capitalizeEveryWord`](#capitalizeeveryword) @@ -156,7 +156,7 @@ * [`truncateString`](#truncatestring) * [`words`](#words) -### Utility +### Utility * [`coalesce`](#coalesce) * [`coalesceFactory`](#coalescefactory) * [`extendHex`](#extendhex) @@ -177,7 +177,7 @@ * [`UUIDGenerator`](#uuidgenerator) * [`validateNumber`](#validatenumber) -## Adapter +## Adapter ### call @@ -204,8 +204,9 @@ Promise.resolve([1, 2, 3]) - +
[⬆ Back to top](#table-of-contents) +--- ### collectInto @@ -230,8 +231,9 @@ Pall(p1, p2, p3).then(console.log); - +
[⬆ Back to top](#table-of-contents) +--- ### flip @@ -258,63 +260,66 @@ 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 +```
- +
[⬆ Back to top](#table-of-contents) +--- ### spreadOver @@ -337,1275 +342,1326 @@ arrayMax([1, 2, 4]); // 4 - +
[⬆ Back to top](#table-of-contents) -## Array - -### arrayGcd - -Calculates the greatest common denominator (gcd) of an array of numbers. - -Use `Array.reduce()` and the `gcd` formula (uses recursion) to calculate the greatest common denominator of an array of numbers. - -```js -const arrayGcd = arr => { - const gcd = (x, y) => (!y ? x : gcd(y, x % y)); - return arr.reduce((a, b) => gcd(a, b)); -}; -``` +--- +## Array +### arrayGcd + +Calculates the greatest common denominator (gcd) of an array of numbers. + +Use `Array.reduce()` and the `gcd` formula (uses recursion) to calculate the greatest common denominator of an array of numbers. + +```js +const arrayGcd = arr => { + const gcd = (x, y) => (!y ? x : gcd(y, x % y)); + return arr.reduce((a, b) => gcd(a, b)); +}; +``` +
Examples -```js -arrayGcd([1, 2, 3, 4, 5]); // 1 -arrayGcd([4, 8, 12]); // 4 -``` +```js +arrayGcd([1, 2, 3, 4, 5]); // 1 +arrayGcd([4, 8, 12]); // 4 +```
- +
[⬆ Back to top](#table-of-contents) +--- -### arrayLcm - -Calculates the lowest common multiple (lcm) of an array of numbers. - -Use `Array.reduce()` and the `lcm` formula (uses recursion) to calculate the lowest common multiple of an array of numbers. - -```js -const arrayLcm = 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)); -}; -``` - +### arrayLcm + +Calculates the lowest common multiple (lcm) of an array of numbers. + +Use `Array.reduce()` and the `lcm` formula (uses recursion) to calculate the lowest common multiple of an array of numbers. + +```js +const arrayLcm = 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 -arrayLcm([1, 2, 3, 4, 5]); // 60 -arrayLcm([4, 8, 12]); // 24 -``` +```js +arrayLcm([1, 2, 3, 4, 5]); // 60 +arrayLcm([4, 8, 12]); // 24 +```
- +
[⬆ Back to top](#table-of-contents) +--- -### arrayMax - -Returns the maximum value in an array. - -Use `Math.max()` combined with the spread operator (`...`) to get the maximum value in the array. - -```js -const arrayMax = arr => Math.max(...arr); -``` - +### arrayMax + +Returns the maximum value in an array. + +Use `Math.max()` combined with the spread operator (`...`) to get the maximum value in the array. + +```js +const arrayMax = arr => Math.max(...arr); +``` +
Examples -```js -arrayMax([10, 1, 5]); // 10 -``` +```js +arrayMax([10, 1, 5]); // 10 +```
- +
[⬆ Back to top](#table-of-contents) +--- -### arrayMin - -Returns the minimum value in an array. - -Use `Math.min()` combined with the spread operator (`...`) to get the minimum value in the array. - -```js -const arrayMin = arr => Math.min(...arr); -``` - +### arrayMin + +Returns the minimum value in an array. + +Use `Math.min()` combined with the spread operator (`...`) to get the minimum value in the array. + +```js +const arrayMin = arr => Math.min(...arr); +``` +
Examples -```js -arrayMin([10, 1, 5]); // 1 -``` +```js +arrayMin([10, 1, 5]); // 1 +```
- +
[⬆ Back to top](#table-of-contents) +--- -### 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, value) => arr.reduce((a, v) => (v === value ? 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, value) => arr.reduce((a, v) => (v === value ? 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.find()` to find the appropriate values. - -```js -const differenceWith = (arr, val, comp) => arr.filter(a => !val.find(b => comp(a, b))); -``` - +### differenceWith + +Filters out all values from an array for which the comparator function does not return `true`. + +Use `Array.filter()` and `Array.find()` to find the appropriate values. + +```js +const differenceWith = (arr, val, comp) => arr.filter(a => !val.find(b => comp(a, b))); +``` +
Examples -```js -differenceWith([1, 1.2, 1.5, 3], [1.9, 3], (a, b) => Math.round(a) == Math.round(b)); // [1, 1.2] -``` +```js +differenceWith([1, 1.2, 1.5, 3], [1.9, 3], (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 and concatenate it with the spread input array causing a shallow denesting of any contained arrays. - -```js -const flatten = arr => [].concat(...arr); -``` - +### flatten + +Flattens an array. + +Use a new array and concatenate it with the spread input array causing 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) +--- -### 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. - -Use `Array((end + 1) - start)` to create an array of the desired length, `Array.map()` to fill with the desired values in a range. -You can omit `start` to use a default value of `0`. - -```js -const initializeArrayWithRange = (end, start = 0) => - Array.from({ length: end + 1 - start }).map((v, i) => i + start); -``` - +### initializeArrayWithRange + +Initializes an array containing the numbers in the specified range where `start` and `end` are inclusive. + +Use `Array((end + 1) - start)` to create an array of the desired length, `Array.map()` to fill with the desired values in a range. +You can omit `start` to use a default value of `0`. + +```js +const initializeArrayWithRange = (end, start = 0) => + Array.from({ length: end + 1 - start }).map((v, i) => i + start); +``` +
Examples -```js -initializeArrayWithRange(5); // [0,1,2,3,4,5] -initializeArrayWithRange(7, 3); // [3,4,5,6,7] -``` +```js +initializeArrayWithRange(5); // [0,1,2,3,4,5] +initializeArrayWithRange(7, 3); // [3,4,5,6,7] +```
- +
[⬆ 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 `value` to use a default value of `0`. - -```js -const initializeArrayWithValues = (n, value = 0) => Array(n).fill(value); -``` - +### 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 `value` to use a default value of `0`. + +```js +const initializeArrayWithValues = (n, value = 0) => Array(n).fill(value); +``` +
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) +--- -### 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) +--- -### 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 myArray1 = ['a', 'b', 'c', 'a', 'b', 'c']; -pull(myArray1, 'a', 'c'); -console.log(myArray1); // [ 'b', 'b' ] - -let myArray2 = ['a', 'b', 'c', 'a', 'b', 'c']; -pull(myArray2, ['a', 'c']); -console.log(myArray2); // [ 'b', 'b' ] -``` +```js +let myArray1 = ['a', 'b', 'c', 'a', 'b', 'c']; +pull(myArray1, 'a', 'c'); +console.log(myArray1); // [ 'b', 'b' ] + +let myArray2 = ['a', 'b', 'c', 'a', 'b', 'c']; +pull(myArray2, ['a', 'c']); +console.log(myArray2); // [ '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]); - -console.log(myArray); // [ 'a', 'c' ] -console.log(pulled); // [ 'b', 'd' ] -``` +```js +let myArray = ['a', 'b', 'c', 'd']; +let pulled = pullAtIndex(myArray, [1, 3]); + +console.log(myArray); // [ 'a', 'c' ] +console.log(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']); -console.log(myArray); // [ 'a', 'c' ] -console.log(pulled); // [ 'b', 'd' ] -``` +```js +let myArray = ['a', 'b', 'c', 'd']; +let pulled = pullAtValue(myArray, ['b', 'd']); +console.log(myArray); // [ 'a', 'c' ] +console.log(pulled); // [ 'b', 'd' ] +```
- +
[⬆ 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) +--- -### shuffle - -Randomizes the order of the values of an array, returning a new array. - -Uses the Fisher-Yates algoritm to reorder the elements of the array, based on the [Lodash implementation](https://github.com/lodash/lodash/blob/b2ea6b1cd251796dcb5f9700c4911a7b6223920b/shuffle.js), but as a pure function. - -```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 algoritm to reorder the elements of the array, based on the [Lodash implementation](https://github.com/lodash/lodash/blob/b2ea6b1cd251796dcb5f9700c4911a7b6223920b/shuffle.js), but as a pure function. + +```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] -console.log(foo); // [1,2,3] -``` +```js +const foo = [1, 2, 3]; +shuffle(foo); // [2,3,1] +console.log(foo); // [1,2,3] +```
- +
[⬆ Back to top](#table-of-contents) +--- -### similarity - -Returns an array of elements that appear in both arrays. - -Use `filter()` to remove values that are not part of `values`, determined using `includes()`. - -```js -const similarity = (arr, values) => arr.filter(v => values.includes(v)); -``` - +### similarity + +Returns an array of elements that appear in both arrays. + +Use `filter()` to remove values that are not part of `values`, determined using `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) +--- -### 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 `arr.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 `arr.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} +```
- +
[⬆ Back to top](#table-of-contents) -## 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}
    • `)); -``` +--- +## 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}
    • `)); +``` +
    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 +```
    - +
    [⬆ 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" -detectDeviceType(); // "Desktop" -``` +```js +detectDeviceType(); // "Mobile" +detectDeviceType(); // "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) +--- -### getURLParameters - -Returns an object containing the parameters of the current URL. - -Use `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 `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'} +```
    - +
    [⬆ 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. - +### 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. +
    Examples @@ -1613,2185 +1669,2269 @@ Use `location.protocol` to get the protocol currently being used. If it's not HT const httpsRedirect = () => { if (location.protocol !== 'https:') location.replace('https://' + location.href.split('//')[1]); }; -``` +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### redirect +### 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 -Redirects to a specified URL. +```js +redirect('https://google.com'); +``` -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); -``` +
    +[⬆ 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); + } +}; +``` +
    Examples -```js -redirect('https://google.com'); -``` +```js +scrollToTop(); +```
    - +
    [⬆ Back to top](#table-of-contents) +--- +## Date -### scrollToTop +### 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 -Smooth-scrolls to the top of the page. +```js +getDaysDiffBetweenDates(new Date('2017-12-13'), new Date('2017-12-22')); // 9 +``` -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); - } -}; -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### JSONToDate + +Converts a JSON object to a date. + +Use `Date()`, to convert dates in JSON format to readable format (`dd/mm/yyyy`). + +```js +const JSONToDate = arr => { + const dt = new Date(parseInt(arr.toString().substr(6))); + return `${dt.getDate()}/${dt.getMonth() + 1}/${dt.getFullYear()}`; +}; +``` +
    Examples -```js -scrollToTop(); -``` +```js +JSONToDate(/Date(1489525200000)/); // "14/3/2017" +```
    - +
    [⬆ Back to top](#table-of-contents) -## Date +--- -### getDaysDiffBetweenDates +### 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 -Returns the difference (in days) between two dates. +```js +toEnglishDate('09/21/2010'); // '21/09/2010' +``` -Calculate the difference (in days) between two `Date` objects. +
    -```js -const getDaysDiffBetweenDates = (dateInitial, dateFinal) => - (dateFinal - dateInitial) / (1000 * 3600 * 24); -``` +
    +[⬆ 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 `toISOString` to convert Date object to string. + +```js +const tomorrow = () => new Date(new Date().getTime() + 86400000).toISOString().split('T')[0]; +``` +
    Examples -```js -getDaysDiffBetweenDates(new Date('2017-12-13'), new Date('2017-12-22')); // 9 -``` +```js +tomorrow(); // 2017-12-27 (if current date is 2017-12-26) +```
    - +
    [⬆ Back to top](#table-of-contents) +--- +## Function -### JSONToDate +### 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 -Converts a JSON object to a date. +```js +chainAsync([ + next => { + console.log('0 seconds'); + setTimeout(next, 1000); + }, + next => { + console.log('1 second'); + setTimeout(next, 1000); + }, + next => { + console.log('2 seconds'); + } +]); +``` -Use `Date()`, to convert dates in JSON format to readable format (`dd/mm/yyyy`). +
    -```js -const JSONToDate = arr => { - const dt = new Date(parseInt(arr.toString().substr(6))); - return `${dt.getDate()}/${dt.getMonth() + 1}/${dt.getFullYear()}`; -}; -``` +
    +[⬆ 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))); +``` +
    Examples -```js -JSONToDate(/Date(1489525200000)/); // "14/3/2017" -``` +```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) +--- -### toEnglishDate +### 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 -Converts a date from American format to English format. +```js +curry(Math.pow)(2)(10); // 1024 +curry(Math.min, 3)(10)(50)(2); // 2 +``` -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) {} -}; -``` +
    +[⬆ 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); +``` +
    Examples -```js -toEnglishDate('09/21/2010'); // '21/09/2010' -``` +```js +functionName(Math.max); // max (logged in debug channel of console) +```
    - +
    [⬆ 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 `toISOString` to convert Date object to string. - -```js -const tomorrow = () => new Date(new Date().getTime() + 86400000).toISOString().split('T')[0]; -``` - +### 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 -tomorrow(); // 2017-12-27 (if current date is 2017-12-26) -``` +```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) -## Function +--- -### chainAsync +### 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 -Chains asynchronous functions. +```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.'); +} +``` -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(); -}; -``` +
    +[⬆ Back to top](#table-of-contents) +--- +## Logic +### negate + +Negates a predicate function. + +Take a predicate function and apply `not` to it with its arguments. + +```js +const negate = func => (...args) => !func(...args); +``` +
    Examples -```js -chainAsync([ - next => { - console.log('0 seconds'); - setTimeout(next, 1000); - }, - next => { - console.log('1 second'); - setTimeout(next, 1000); - }, - next => { - console.log('2 seconds'); - } -]); -``` +```js +filter([1, 2, 3, 4, 5, 6], negate(isEven)); // [1, 3, 5] +negate(isOdd)(1); // false +```
    - +
    [⬆ Back to top](#table-of-contents) +--- +## Math -### compose +### arrayAverage + +Returns the average of an array of 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 arrayAverage = arr => arr.reduce((acc, val) => acc + val, 0) / arr.length; +``` + +
    +Examples -Performs right-to-left function composition. +```js +arrayAverage([1, 2, 3]); // 2 +``` -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))); -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### arraySum + +Returns the sum of an array of numbers. + +Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`. + +```js +const arraySum = arr => arr.reduce((acc, val) => acc + val, 0); +``` +
    Examples -```js -const add5 = x => x + 5; -const multiply = (x, y) => x * y; -const multiplyAndAdd5 = compose(add5, multiply); -multiplyAndAdd5(5, 2); // 15 -``` +```js +arraySum([1, 2, 3, 4]); // 10 +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### curry +### 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 -Curries a function. +```js +clampNumber(2, 3, 5); // 3 +clampNumber(1, -1, -5); // -1 +clampNumber(3, 2, 4); // 3 +``` -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); -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### collatz + +Applies the Collatz algorithm. + +If `n` is even, return `n/2`. Otherwise, return `3n+1`. + +```js +const collatz = n => (n % 2 == 0 ? n / 2 : 3 * n + 1); +``` +
    Examples -```js -curry(Math.pow)(2)(10); // 1024 -curry(Math.min, 3)(10)(50)(2); // 2 -``` +```js +collatz(8); // 4 +collatz(5); // 16 +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### functionName +### digitize + +Converts a number to an array of digits. + +Convert the number to a string, using spread operators in ES6(`[...string]`) 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 -Logs the name of a function. +```js +digitize(123); // [1, 2, 3] +``` -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); -``` +
    +[⬆ 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); +``` +
    Examples -```js -functionName(Math.max); // max (logged in debug channel of console) -``` +```js +distance(1, 1, 2, 3); // 2.23606797749979 +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### runPromisesInSeries +### 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 -Runs an array of promises in series. +```js +factorial(6); // 720 +``` -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()); -``` +
    +[⬆ 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), + [] + ); +``` +
    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 +fibonacci(6); // 720 +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### sleep +### fibonacciCountUntilNum + +Returns the number of fibonnacci numbers up to `num`(`0` and `num` inclusive). + +Use a mathematical formula to calculate the number of fibonacci numbers until `num`. + +```js +const fibonacciCountUntilNum = num => + Math.ceil(Math.log(num * Math.sqrt(5) + 1 / 2) / Math.log((Math.sqrt(5) + 1) / 2)); +``` + +
    +Examples -Delays the execution of an asynchronous function. +```js +fibonacciCountUntilNum(10); // 7 +``` -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)); -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### fibonacciUntilNum + +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. +Uses a mathematical formula to calculate the length of the array required. + +```js +const fibonacciUntilNum = num => { + let n = Math.ceil(Math.log(num * Math.sqrt(5) + 1 / 2) / Math.log((Math.sqrt(5) + 1) / 2)); + return Array.from({ length: n }).reduce( + (acc, val, i) => acc.concat(i > 1 ? acc[i - 1] + acc[i - 2] : i), + [] + ); +}; +``` +
    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 +fibonacciCountUntilNum(10); // 7 +```
    - +
    [⬆ Back to top](#table-of-contents) -## Logic +--- -### negate +### gcd + +Calculates the greatest common divisor between two numbers. + +Use 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 = (x, y) => (!y ? x : gcd(y, x % y)); +``` + +
    +Examples -Negates a predicate function. +```js +gcd(8, 36); // 4 +``` -Take a predicate function and apply `not` to it with its arguments. +
    -```js -const negate = func => (...args) => !func(...args); -``` +
    +[⬆ 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; +``` +
    Examples -```js -filter([1, 2, 3, 4, 5, 6], negate(isEven)); // [1, 3, 5] -negate(isOdd)(1); // false -``` +```js +hammingDistance(2, 3); // 1 +```
    - +
    [⬆ Back to top](#table-of-contents) -## Math +--- -### arrayAverage +### 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 -Returns the average of an array of numbers. +```js +inRange(3, 2, 5); // true +inRange(3, 4); // true +inRange(2, 3, 5); // false +inrange(3, 2); // false +``` -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 arrayAverage = arr => arr.reduce((acc, val) => acc + val, 0) / arr.length; -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### isArmstrongNumber + +Checks if the given number is an Armstrong number or not. + +Convert the given number into an array of digits. Use `Math.pow()` to get the appropriate power for each digit and sum them up. If the sum is equal to the number itself, return `true` otherwise `false`. + +```js +const isArmstrongNumber = digits => + (arr => arr.reduce((a, d) => a + Math.pow(parseInt(d), arr.length), 0) == digits)( + (digits + '').split('') + ); +``` +
    Examples -```js -arrayAverage([1, 2, 3]); // 2 -``` +```js +isArmstrongNumber(1634); // true +isArmstrongNumber(371); // true +isArmstrongNumber(56); // false +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### arraySum +### 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 -Returns the sum of an array of numbers. +```js +isDivisible(6, 3); // true +``` -Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`. +
    -```js -const arraySum = arr => arr.reduce((acc, val) => acc + val, 0); -``` +
    +[⬆ 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; +``` +
    Examples -```js -arraySum([1, 2, 3, 4]); // 10 -``` +```js +isEven(3); // false +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### clampNumber +### 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 * i <= boundary; i++) if (num % i == 0) return false; + return num >= 2; +}; +``` + +
    +Examples -Clamps `num` within the inclusive range specified by the boundary values `a` and `b`. +```js +isPrime(11); // true +isPrime(12); // false +``` -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)); -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### lcm + +Returns the least common multiple of two 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 = (x, y) => { + const gcd = (x, y) => (!y ? x : gcd(y, x % y)); + return Math.abs(x * y) / gcd(x, y); +}; +``` +
    Examples -```js -clampNumber(2, 3, 5); // 3 -clampNumber(1, -1, -5); // -1 -clampNumber(3, 2, 4); // 3 -``` +```js +lcm(12, 7); // 84 +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### collatz +### 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 -Applies the Collatz algorithm. +```js +median([5, 6, 50, 1, -5]); // 5 +median([0, 10, -2, 7]); // 3.5 +``` -If `n` is even, return `n/2`. Otherwise, return `3n+1`. +
    -```js -const collatz = n => (n % 2 == 0 ? n / 2 : 3 * n + 1); -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### palindrome + +Returns `true` if the given string is a palindrome, `false` otherwise. + +Convert string `toLowerCase()` and use `replace()` to remove non-alphanumeric characters from it. +Then, `split('')` into individual characters, `reverse()`, `join('')` and compare to the original, unreversed string, after converting it `tolowerCase()`. + +```js +const palindrome = str => { + const s = str.toLowerCase().replace(/[\W_]/g, ''); + return ( + s === + s + .split('') + .reverse() + .join('') + ); +}; +``` +
    Examples -```js -collatz(8); // 4 -collatz(5); // 16 -``` +```js +palindrome('taco cat'); // true +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### digitize +### 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 -Converts a number to an array of digits. +```js +percentile([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 6); // 55 +``` -Convert the number to a string, using spread operators in ES6(`[...string]`) build an array. -Use `Array.map()` and `parseInt()` to transform each value to an integer. +
    -```js -const digitize = n => [...('' + n)].map(i => parseInt(i)); -``` +
    +[⬆ 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))), [[]]); +``` +
    Examples -```js -digitize(123); // [1, 2, 3] -``` +```js +powerset([1, 2]); // [[], [1], [2], [2,1]] +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### distance +### 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 -Returns the distance between two points. +```js +primes(10); // [2,3,5,7] +``` -Use `Math.hypot()` to calculate the Euclidean distance between two points. +
    -```js -const distance = (x0, y0, x1, y1) => Math.hypot(x1 - x0, y1 - y0); -``` +
    +[⬆ 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; +``` +
    Examples -```js -distance(1, 1, 2, 3); // 2.23606797749979 -``` +```js +randomIntegerInRange(0, 5); // 2 +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### factorial +### 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 -Calculates the factorial of a number. +```js +randomNumberInRange(2, 10); // 6.0211363285087005 +``` -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); -``` +
    +[⬆ 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}`); +``` +
    Examples -```js -factorial(6); // 720 -``` +```js +round(1.005, 2); // 1.01 +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### fibonacci +### 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(Math.pow(val - mean, 2)), []) + .reduce((acc, val) => acc + val, 0) / + (arr.length - (usePopulation ? 0 : 1)) + ); +}; +``` + +
    +Examples -Generates an array, containing the Fibonacci sequence, up until the nth term. +```js +standardDeviation([10, 2, 38, 23, 38, 23, 21]); // 13.284434142114991 (sample) +standardDeviation([10, 2, 38, 23, 38, 23, 21], true); // 12.29899614287479 (population) +``` -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), - [] - ); -``` +
    +[⬆ Back to top](#table-of-contents) +--- +## Media +### speechSynthesis + +Performs speech synthesis (experimental). + +Use `SpeechSynthesisUtterance.voice` and `window.speechSynthesis.getVoices()` to convert a message to speech. +Use `window.speechSynthesis.speak()` to play the message. + +Learn more about the [SpeechSynthesisUtterance interface of the Web Speech API](https://developer.mozilla.org/en-US/docs/Web/API/SpeechSynthesisUtterance). + +```js +const speechSynthesis = message => { + const msg = new SpeechSynthesisUtterance(message); + msg.voice = window.speechSynthesis.getVoices()[0]; + window.speechSynthesis.speak(msg); +}; +``` +
    Examples -```js -fibonacci(6); // 720 -``` +```js +speechSynthesis('Hello, World'); // // plays the message +```
    - +
    [⬆ Back to top](#table-of-contents) +--- +## Node -### fibonacciCountUntilNum +### 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 -Returns the number of fibonnacci numbers up to `num`(`0` and `num` inclusive). +```js +JSONToFile({ test: 'is passed' }, 'testJsonFile'); // writes the object to 'testJsonFile.json' +``` -Use a mathematical formula to calculate the number of fibonacci numbers until `num`. +
    -```js -const fibonacciCountUntilNum = num => - Math.ceil(Math.log(num * Math.sqrt(5) + 1 / 2) / Math.log((Math.sqrt(5) + 1) / 2)); -``` +
    +[⬆ 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'); +``` +
    Examples -```js -fibonacciCountUntilNum(10); // 7 -``` +```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) +--- +## Object -### fibonacciUntilNum +### 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 `include`d in given array. +Also if you give it a special key (`childIndicator`) it will search deeply inside it to apply 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 -Generates an array, containing the Fibonacci sequence, up until the nth term. +```js +const testObj = { a: 1, b: 2, children: { a: 1, b: 2 } }; +cleanObj(testObj, ['a'], 'children'); // { a: 1, children : { a: 1}} +``` -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. -Uses a mathematical formula to calculate the length of the array required. +
    -```js -const fibonacciUntilNum = num => { - let n = Math.ceil(Math.log(num * Math.sqrt(5) + 1 / 2) / Math.log((Math.sqrt(5) + 1) / 2)); - return Array.from({ length: n }).reduce( - (acc, val, i) => acc.concat(i > 1 ? acc[i - 1] + acc[i - 2] : i), - [] - ); -}; -``` +
    +[⬆ 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), {}); +``` +
    Examples -```js -fibonacciCountUntilNum(10); // 7 -``` +```js +objectFromPairs([['a', 1], ['b', 2]]); // {a: 1, b: 2} +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### gcd +### 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 -Calculates the greatest common divisor between two numbers. +```js +objectToPairs({ a: 1, b: 2 }); // [['a',1],['b',2]]) +``` -Use 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 = (x, y) => (!y ? x : gcd(y, x % y)); -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### orderBy + +Returns a sorted array of objects ordered by properties and orders. + +Uses a custom implementation of sort, that reduces the props array argument with a default value of 0, it uses 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 -gcd(8, 36); // 4 -``` +```js +const users = [ + { name: 'fred', age: 48 }, + { name: 'barney', age: 36 }, + { name: 'fred', age: 40 }, + { name: 'barney', age: 34 } +]; +orderBy(users, ['name', 'age'], ['asc', 'desc']); // [{name: 'barney', age: 36}, {name: 'barney', age: 34}, {name: 'fred', age: 48}, {name: 'fred', age: 40}] +orderBy(users, ['name', 'age']); // [{name: 'barney', age: 34}, {name: 'barney', age: 36}, {name: 'fred', age: 40}, {name: 'fred', age: 48}] +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### hammingDistance +### select + +Retrieve a property that 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 -Calculates the Hamming distance between two values. +```js +const obj = { selector: { to: { val: 'val to select' } } }; +select(obj, 'selector.to.val'); // 'val to select' +``` -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; -``` +
    +[⬆ 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); +``` +
    Examples -```js -hammingDistance(2, 3); // 1 -``` +```js +const a = { x: true, y: 1 }; +const b = shallowClone(a); +a === b; // false +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### inRange +### 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 -Checks if the given number falls within the given range. +```js +truthCheckCollection([{ user: 'Tinky-Winky', sex: 'male' }, { user: 'Dipsy', sex: 'male' }], 'sex'); // true +``` -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; -}; -``` +
    +[⬆ Back to top](#table-of-contents) +--- +## String +### anagrams + +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 -inRange(3, 2, 5); // true -inRange(3, 4); // true -inRange(2, 3, 5); // false -inrange(3, 2); // false -``` +```js +anagrams('abc'); // ['abc','acb','bac','bca','cab','cba'] +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### isArmstrongNumber +### Capitalize + +Capitalizes the first letter of a string. + +Use destructuring and `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 -Checks if the given number is an Armstrong number or not. +```js +capitalize('fooBar'); // 'FooBar' +capitalize('fooBar', true); // 'Foobar' +``` -Convert the given number into an array of digits. Use `Math.pow()` to get the appropriate power for each digit and sum them up. If the sum is equal to the number itself, return `true` otherwise `false`. +
    -```js -const isArmstrongNumber = digits => - (arr => arr.reduce((a, d) => a + Math.pow(parseInt(d), arr.length), 0) == digits)( - (digits + '').split('') - ); -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### capitalizeEveryWord + +Capitalizes the first letter of every word in a string. + +Use `replace()` to match the first character of each word and `toUpperCase()` to capitalize it. + +```js +const capitalizeEveryWord = str => str.replace(/\b[a-z]/g, char => char.toUpperCase()); +``` +
    Examples -```js -isArmstrongNumber(1634); // true -isArmstrongNumber(371); // true -isArmstrongNumber(56); // false -``` +```js +capitalizeEveryWord('hello world!'); // 'Hello World!' +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### isDivisible +### 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 -Checks if the first numeric argument is divisible by the second one. +```js +countVowels('foobar'); // 3 +countVowels('gym'); // 0 +``` -Use the modulo operator (`%`) to check if the remainder is equal to `0`. +
    -```js -const isDivisible = (dividend, divisor) => dividend % divisor === 0; -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### escapeRegExp + +Escapes a string to use in a regular expression. + +Use `replace()` to escape special characters. + +```js +const escapeRegExp = str => str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); +``` +
    Examples -```js -isDivisible(6, 3); // true -``` +```js +escapeRegExp('(test)'); // \\(test\\) +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### isEven +### fromCamelCase + +Converts a string from camelcase. + +Use `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 -Returns `true` if the given number is even, `false` otherwise. +```js +fromCamelCase('someDatabaseFieldName', ' '); // 'some database field name' +fromCamelCase('someLabelThatNeedsToBeCamelized', '-'); // 'some-label-that-needs-to-be-camelized' +fromCamelCase('someJavascriptProperty', '_'); // 'some_javascript_property' +``` -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; -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### repeatString + +Repeats a string n times using `String.repeat()` + +If no string is provided the default is `""` and the default number of times is 2. + +```js +const repeatString = (str = '', num = 2) => { + return num >= 0 ? str.repeat(num) : str; +}; +``` +
    Examples -```js -isEven(3); // false -``` +```js +repeatString('abc', 3); // 'abcabcabc' +repeatString('abc'); // 'abcabc' +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### isPrime +### reverseString + +Reverses a string. + +Use `split('')` and `Array.reverse()` to reverse the order of the characters in the string. +Combine characters to get a string using `join('')`. + +```js +const reverseString = str => + str + .split('') + .reverse() + .join(''); +``` + +
    +Examples -Checks if the provided integer is a prime number. +```js +reverseString('foobar'); // 'raboof' +``` -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 * i <= boundary; i++) if (num % i == 0) return false; - return num >= 2; -}; -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### sortCharactersInString + +Alphabetically sorts the characters in a string. + +Split the string using `split('')`, `Array.sort()` utilizing `localeCompare()`, recombine using `join('')`. + +```js +const sortCharactersInString = str => + str + .split('') + .sort((a, b) => a.localeCompare(b)) + .join(''); +``` +
    Examples -```js -isPrime(11); // true -isPrime(12); // false -``` +```js +sortCharactersInString('cabbage'); // 'aabbceg' +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### lcm +### toCamelCase + +Converts a string to camelcase. + +Break the string into words and combine them capitalizing the first letter of each word. +For more detailed explanation of this Regex, [visit this Site](https://regex101.com/r/bMCgAB/1). + +```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 -Returns the least common multiple of two numbers. +```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' +``` -Use the greatest common divisor (GCD) formula and `Math.abs()` to determine the least common multiple. -The GCD formula uses recursion. +
    -```js -const lcm = (x, y) => { - const gcd = (x, y) => (!y ? x : gcd(y, x % y)); - return Math.abs(x * y) / gcd(x, y); -}; -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### toKebabCase + +Converts a string to kebab case. + +Break the string into words and combine them using `-` as a separator. +For more detailed explanation of this Regex, [visit this Site](https://regex101.com/r/bMCgAB/1). + +```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 -lcm(12, 7); // 84 -``` +```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) +--- -### median +### toSnakeCase + +Converts a string to snake case. + +Break the string into words and combine them using `_` as a separator. +For more detailed explanation of this Regex, [visit this Site](https://regex101.com/r/bMCgAB/1). + +```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 -Returns the median of an array of numbers. +```js +toSnakeCase('camelCase'); // 'camel_case' +toSnakeCase('some text'); // 'some_text' +toSnakeCase('some-javascript-property'); // 'some_javascript_property' +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" +``` -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; -}; -``` +
    +[⬆ 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; +``` +
    Examples -```js -median([5, 6, 50, 1, -5]); // 5 -median([0, 10, -2, 7]); // 3.5 -``` +```js +truncateString('boomerang', 7); // 'boom...' +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### palindrome +### words + +Converts a given string into an array of words. + +Use `String.split()` with a supplied pattern (defaults to non-alpha as a regex) to convert to an array of strings. Use `Array.filter()` to remove any empty strings. +Omit the second argument to use the default regex. + +```js +const words = (str, pattern = /[^a-zA-Z-]+/) => str.split(pattern).filter(Boolean); +``` + +
    +Examples -Returns `true` if the given string is a palindrome, `false` otherwise. +```js +words('I love javaScript!!'); // ["I", "love", "javaScript"] +words('python, javaScript & coffee'); // ["python", "javaScript", "coffee"] +``` -Convert string `toLowerCase()` and use `replace()` to remove non-alphanumeric characters from it. -Then, `split('')` into individual characters, `reverse()`, `join('')` and compare to the original, unreversed string, after converting it `tolowerCase()`. +
    -```js -const palindrome = str => { - const s = str.toLowerCase().replace(/[\W_]/g, ''); - return ( - s === - s - .split('') - .reverse() - .join('') - ); -}; -``` +
    +[⬆ Back to top](#table-of-contents) +--- +## Utility +### 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 -palindrome('taco cat'); // true -``` +```js +coalesce(null, undefined, '', NaN, 'Waldo'); // "" +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### percentile +### 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 -Uses the percentile formula to calculate how many numbers in the given array are less or equal to the given value. +```js +const customCoalesce = coalesceFactory(_ => ![null, undefined, '', NaN].includes(_)); +customCoalesce(undefined, null, NaN, '', 'Waldo'); // "Waldo" +``` -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; -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### extendHex + +Extends a 3-digit color code to a 6-digit color code. + +Use `Array.map()`, `split()` and `Array.join()` to join the mapped array for converting a 3-digit RGB notated hexadecimal color-code to the 6-digit form. +`String.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 -percentile([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 6); // 55 -``` +```js +extendHex('#03f'); // '#0033ff' +extendHex('05a'); // '#0055aa' +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### powerset +### 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 -Returns the powerset of a given array of numbers. +```js +getType(new Set([1, 2, 3])); // "set" +``` -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))), [[]]); -``` +
    +[⬆ Back to top](#table-of-contents) +--- +### hexToRGB + +Converts a color code to a `rgb()` or `rgba()` string if alpha value is provided. + +Use bitwise right-shift operator and mask bits with `&` (and) operator to convert a hexadecimal color code (with or without prefixed with `#`) to a string with the RGB values. If it's 3-digit color code, first convert to 6-digit version. If an alpha value is provided alongside 6-digit hex, give `rgba()` string in return. + +```js +const hexToRGB = hex => { + let alpha = false, + h = hex.slice(hex.startsWith('#') ? 1 : 0); + if (h.length === 3) h = [...h].map(x => x + x).join(''); + else if (h.length === 8) alpha = true; + h = parseInt(h, 16); + return ( + 'rgb' + + (alpha ? 'a' : '') + + '(' + + (h >>> (alpha ? 24 : 16)) + + ', ' + + ((h & (alpha ? 0x00ff0000 : 0x00ff00)) >>> (alpha ? 16 : 8)) + + ', ' + + ((h & (alpha ? 0x0000ff00 : 0x0000ff)) >>> (alpha ? 8 : 0)) + + (alpha ? `, ${h & 0x000000ff}` : '') + + ')' + ); +}; +``` +
    Examples -```js -powerset([1, 2]); // [[], [1], [2], [2,1]] -``` +```js +hexToRGB('#27ae60ff'); // 'rgba(39, 174, 96, 255)' +hexToRGB('27ae60'); // 'rgb(39, 174, 96)' +hexToRGB('#fff'); // 'rgb(255, 255, 255)' +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### primes +### 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 => !!val && Array.isArray(val); +``` + +
    +Examples -Generates primes up to a given number, using the Sieve of Eratosthenes. +```js +isArray(null); // false +isArray([1]); // true +``` -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; -}; -``` +
    +[⬆ 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'; +``` +
    Examples -```js -primes(10); // [2,3,5,7] -``` +```js +isBoolean(null); // false +isBoolean(false); // true +```
    - +
    [⬆ Back to top](#table-of-contents) +--- -### randomIntegerInRange +### 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 => val && typeof val === 'function'; +``` + +
    +Examples -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 -``` - -
    - - -[⬆ 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; -``` - -
    -Examples - -```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}`); -``` - -
    -Examples - -```js -round(1.005, 2); // 1.01 -``` - -
    - - -[⬆ 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(Math.pow(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) -``` - -
    - - -[⬆ Back to top](#table-of-contents) -## Media - -### speechSynthesis - -Performs speech synthesis (experimental). - -Use `SpeechSynthesisUtterance.voice` and `window.speechSynthesis.getVoices()` to convert a message to speech. -Use `window.speechSynthesis.speak()` to play the message. - -Learn more about the [SpeechSynthesisUtterance interface of the Web Speech API](https://developer.mozilla.org/en-US/docs/Web/API/SpeechSynthesisUtterance). - -```js -const speechSynthesis = message => { - const msg = new SpeechSynthesisUtterance(message); - msg.voice = window.speechSynthesis.getVoices()[0]; - window.speechSynthesis.speak(msg); -}; -``` - -
    -Examples - -```js -speechSynthesis('Hello, World'); // // plays the message -``` - -
    - - -[⬆ Back to top](#table-of-contents) -## Node - -### 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' -``` - -
    - - -[⬆ 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'); -``` - -
    -Examples - -```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) -## 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 `include`d in given array. -Also if you give it a special key (`childIndicator`) it will search deeply inside it to apply 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}} -``` - -
    - - -[⬆ 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), {}); -``` - -
    -Examples - -```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]]); -``` - -
    -Examples - -```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 a custom implementation of sort, that reduces the props array argument with a default value of 0, it uses 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 }, - { name: 'barney', age: 34 } -]; -orderBy(users, ['name', 'age'], ['asc', 'desc']); // [{name: 'barney', age: 36}, {name: 'barney', age: 34}, {name: 'fred', age: 48}, {name: 'fred', age: 40}] -orderBy(users, ['name', 'age']); // [{name: 'barney', age: 34}, {name: 'barney', age: 36}, {name: 'fred', age: 40}, {name: 'fred', age: 48}] -``` - -
    - - -[⬆ Back to top](#table-of-contents) - -### select - -Retrieve a property that 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' -``` - -
    - - -[⬆ 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); -``` - -
    -Examples - -```js -const a = { x: true, y: 1 }; -const b = shallowClone(a); -a === b; // false -``` - -
    - - -[⬆ 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]); -``` - -
    -Examples - -```js -truthCheckCollection([{ user: 'Tinky-Winky', sex: 'male' }, { user: 'Dipsy', sex: 'male' }], 'sex'); // true -``` - -
    - - -[⬆ Back to top](#table-of-contents) -## String - -### anagrams - -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'] -``` - -
    - - -[⬆ Back to top](#table-of-contents) - -### Capitalize - -Capitalizes the first letter of a string. - -Use destructuring and `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' -``` - -
    - - -[⬆ Back to top](#table-of-contents) - -### capitalizeEveryWord - -Capitalizes the first letter of every word in a string. - -Use `replace()` to match the first character of each word and `toUpperCase()` to capitalize it. - -```js -const capitalizeEveryWord = str => str.replace(/\b[a-z]/g, char => char.toUpperCase()); -``` - -
    -Examples - -```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; -``` - -
    -Examples - -```js -countVowels('foobar'); // 3 -countVowels('gym'); // 0 -``` - -
    - - -[⬆ Back to top](#table-of-contents) - -### escapeRegExp - -Escapes a string to use in a regular expression. - -Use `replace()` to escape special characters. - -```js -const escapeRegExp = str => str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); -``` - -
    -Examples - -```js -escapeRegExp('(test)'); // \\(test\\) -``` - -
    - - -[⬆ Back to top](#table-of-contents) - -### fromCamelCase - -Converts a string from camelcase. - -Use `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' -``` - -
    - - -[⬆ Back to top](#table-of-contents) - -### repeatString - -Repeats a string n times using `String.repeat()` - -If no string is provided the default is `""` and the default number of times is 2. - -```js -const repeatString = (str = '', num = 2) => { - return num >= 0 ? str.repeat(num) : str; -}; -``` - -
    -Examples - -```js -repeatString('abc', 3); // 'abcabcabc' -repeatString('abc'); // 'abcabc' -``` - -
    - - -[⬆ Back to top](#table-of-contents) - -### reverseString - -Reverses a string. - -Use `split('')` and `Array.reverse()` to reverse the order of the characters in the string. -Combine characters to get a string using `join('')`. - -```js -const reverseString = str => - str - .split('') - .reverse() - .join(''); -``` - -
    -Examples - -```js -reverseString('foobar'); // 'raboof' -``` - -
    - - -[⬆ Back to top](#table-of-contents) - -### sortCharactersInString - -Alphabetically sorts the characters in a string. - -Split the string using `split('')`, `Array.sort()` utilizing `localeCompare()`, recombine using `join('')`. - -```js -const sortCharactersInString = str => - str - .split('') - .sort((a, b) => a.localeCompare(b)) - .join(''); -``` - -
    -Examples - -```js -sortCharactersInString('cabbage'); // 'aabbceg' -``` - -
    - - -[⬆ 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. -For more detailed explanation of this Regex, [visit this Site](https://regex101.com/r/bMCgAB/1). - -```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' -``` - -
    - - -[⬆ Back to top](#table-of-contents) - -### toKebabCase - -Converts a string to kebab case. - -Break the string into words and combine them using `-` as a separator. -For more detailed explanation of this Regex, [visit this Site](https://regex101.com/r/bMCgAB/1). - -```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" -``` - -
    - - -[⬆ Back to top](#table-of-contents) - -### toSnakeCase - -Converts a string to snake case. - -Break the string into words and combine them using `_` as a separator. -For more detailed explanation of this Regex, [visit this Site](https://regex101.com/r/bMCgAB/1). - -```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-javascript-property'); // 'some_javascript_property' -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; -``` - -
    -Examples - -```js -truncateString('boomerang', 7); // 'boom...' -``` - -
    - - -[⬆ 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 regex) to convert to an array of strings. Use `Array.filter()` to remove any empty strings. -Omit the second argument to use the default regex. - -```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"] -``` - -
    - - -[⬆ Back to top](#table-of-contents) -## Utility - -### 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'); // "" -``` - -
    - - -[⬆ 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); -``` - -
    -Examples - -```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()`, `split()` and `Array.join()` to join the mapped array for converting a 3-digit RGB notated hexadecimal color-code to the 6-digit form. -`String.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' -``` - -
    - - -[⬆ Back to top](#table-of-contents) - -### 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" -``` - -
    - - -[⬆ Back to top](#table-of-contents) - -### hexToRGB - -Converts a color code to a `rgb()` or `rgba()` string if alpha value is provided. - -Use bitwise right-shift operator and mask bits with `&` (and) operator to convert a hexadecimal color code (with or without prefixed with `#`) to a string with the RGB values. If it's 3-digit color code, first convert to 6-digit version. If an alpha value is provided alongside 6-digit hex, give `rgba()` string in return. - -```js -const hexToRGB = hex => { - let alpha = false, - h = hex.slice(hex.startsWith('#') ? 1 : 0); - if (h.length === 3) h = [...h].map(x => x + x).join(''); - else if (h.length === 8) alpha = true; - h = parseInt(h, 16); - return ( - 'rgb' + - (alpha ? 'a' : '') + - '(' + - (h >>> (alpha ? 24 : 16)) + - ', ' + - ((h & (alpha ? 0x00ff0000 : 0x00ff00)) >>> (alpha ? 16 : 8)) + - ', ' + - ((h & (alpha ? 0x0000ff00 : 0x0000ff)) >>> (alpha ? 8 : 0)) + - (alpha ? `, ${h & 0x000000ff}` : '') + - ')' - ); -}; -``` - -
    -Examples - -```js -hexToRGB('#27ae60ff'); // 'rgba(39, 174, 96, 255)' -hexToRGB('27ae60'); // 'rgb(39, 174, 96)' -hexToRGB('#fff'); // 'rgb(255, 255, 255)' -``` - -
    - - -[⬆ 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 => !!val && Array.isArray(val); -``` - -
    -Examples - -```js -isArray(null); // false -isArray([1]); // true -``` - -
    - - -[⬆ 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'; -``` - -
    -Examples - -```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 => 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) +--- -### 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) +--- -### 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); // false -isString('10'); // true -``` +```js +isString(10); // false +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('x'); // false -isSymbol(Symbol('x')); // true -``` +```js +isSymbol('x'); // false +isSymbol(Symbol('x')); // true +```
    - +
    [⬆ 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" -randomHexColorCode(); // "#fd73a6" -randomHexColorCode(); // "#4144c6" -``` +```js +randomHexColorCode(); // "#e34155" +randomHexColorCode(); // "#fd73a6" +randomHexColorCode(); // "#4144c6" +```
    - +
    [⬆ 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 `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 `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) +--- -### sbdm - -This algorithm is a simple hash-algorithm that hashes it input string `s` into a whole number. - -Use `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 + +This algorithm is a simple hash-algorithm that hashes it input string `s` into a whole number. + +Use `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 -console.log(sdbm('age')); // 808122783 -``` +```js +console.log(sdbm('name')); // -3521204949 +console.log(sdbm('age')); // 808122783 +```
    - +
    [⬆ 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) +--- -### UUIDGenerator - -Generates a UUID. - -Use `crypto` API to generate a UUID, compliant with [RFC4122](https://www.ietf.org/rfc/rfc4122.txt) version 4. - -```js -const UUIDGenerator = () => - ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c => - (c ^ (crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (c / 4)))).toString(16) - ); -``` - +### UUIDGenerator + +Generates a UUID. + +Use `crypto` API to generate a UUID, compliant with [RFC4122](https://www.ietf.org/rfc/rfc4122.txt) version 4. + +```js +const UUIDGenerator = () => + ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c => + (c ^ (crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (c / 4)))).toString(16) + ); +``` +
    Examples -```js -UUIDGenerator(); // '7982fcfe-5721-4632-bede-6000885be57d' -``` +```js +UUIDGenerator(); // '7982fcfe-5721-4632-bede-6000885be57d' +```
    - +
    [⬆ 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) +--- -## 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/).* +## 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/).* diff --git a/scripts/build-script.js b/scripts/build-script.js index c0aea77f1..c5c61cced 100644 --- a/scripts/build-script.js +++ b/scripts/build-script.js @@ -79,7 +79,7 @@ try { for(let taggedSnippet of Object.entries(tagDbData).filter(v => v[1] === tag)){ let data = snippets[taggedSnippet[0]+'.md']; data = data.slice(0,data.lastIndexOf('```js')) + '
    \nExamples\n\n' + data.slice(data.lastIndexOf('```js'),data.lastIndexOf('```')) + data.slice(data.lastIndexOf('```')) + '\n
    \n'; - output += `\n${data+'\n\n[⬆ Back to top](#table-of-contents)\n'}`; + output += `\n${data+'\n
    \n[⬆ Back to top](#table-of-contents)\n---\n'}`; } } }