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Merge pull request #4 from Chalarangelo/master

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Stefan Feješ
2017-12-17 14:49:19 +01:00
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node_modules/
currentSnippet\.js
*.md.temp.js
.idea

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CODE_OF_CONDUCT.md Normal file
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# Contributor Covenant Code of Conduct
## Our Pledge
In the interest of fostering an open and welcoming environment, we as contributors and maintainers pledge to making participation in our project and our community a harassment-free experience for everyone, regardless of age, body size, disability, ethnicity, gender identity and expression, level of experience, nationality, personal appearance, race, religion, or sexual identity and orientation.
## Our Standards
Examples of behavior that contributes to creating a positive environment include:
* Using welcoming and inclusive language
* Being respectful of differing viewpoints and experiences
* Gracefully accepting constructive criticism
* Focusing on what is best for the community
* Showing empathy towards other community members
Examples of unacceptable behavior by participants include:
* The use of sexualized language or imagery and unwelcome sexual attention or advances
* Trolling, insulting/derogatory comments, and personal or political attacks
* Public or private harassment
* Publishing others' private information, such as a physical or electronic address, without explicit permission
* Other conduct which could reasonably be considered inappropriate in a professional setting
## Our Responsibilities
Project maintainers are responsible for clarifying the standards of acceptable behavior and are expected to take appropriate and fair corrective action in response to any instances of unacceptable behavior.
Project maintainers have the right and responsibility to remove, edit, or reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct, or to ban temporarily or permanently any contributor for other behaviors that they deem inappropriate, threatening, offensive, or harmful.
## Scope
This Code of Conduct applies both within project spaces and in public spaces when an individual is representing the project or its community. Examples of representing a project or community include using an official project e-mail address, posting via an official social media account, or acting as an appointed representative at an online or offline event. Representation of a project may be further defined and clarified by project maintainers.
## Enforcement
Instances of abusive, harassing, or otherwise unacceptable behavior may be reported by contacting the project team at chalarangelo@gmail.com. The project team will review and investigate all complaints, and will respond in a way that it deems appropriate to the circumstances. The project team is obligated to maintain confidentiality with regard to the reporter of an incident. Further details of specific enforcement policies may be posted separately.
Project maintainers who do not follow or enforce the Code of Conduct in good faith may face temporary or permanent repercussions as determined by other members of the project's leadership.
## Attribution
This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4, available at [http://contributor-covenant.org/version/1/4][version]
[homepage]: http://contributor-covenant.org
[version]: http://contributor-covenant.org/version/1/4/

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CONTRIBUTING.md
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@ -29,6 +29,7 @@ Here's what you can do to help:
- Try to keep your snippets' code short and to the point. Use modern techniques and features. Make sure to test your code before submitting.
- All snippets must be followed by one (more if necessary) test case after the code, on a new line, in the form of a comment, along with the expected output. The syntax for this is `myFunction('testInput') -> 'testOutput'`. Use multiline comments only if necessary.
- Try to make your function name unique, so that it does not conflict with existing snippets.
- Snippet functions do not have to handle errors in input, unless it's necessary (e.g. a mathematical function that cannot be extended to negative numbers should handle negative input appropriately).
- Snippets should be short (usually below 10 lines). If your snippet is longer than that, you can still submit it, and we can help you shorten it or figure out ways to improve it.
- Snippets *should* solve real-world problems, no matter how simple.
- Snippets *should* be abstract enough to be applied to different scenarios.
@ -54,7 +55,8 @@ Here's what you can do to help:
- `i` for indexes.
- `func` for function arguments.
- `nums` for arrays of numbers.
- Use `_` if your function takes no arguments or if an argument inside some function (e.g. `Array.reduce()`) is not used anywhere in your code.
- Use `()` if your function takes no arguments.
- Use `_` if an argument inside some function (e.g. `Array.reduce()`) is not used anywhere in your code.
- Specify default parameters for arguments, if necessary. It is preferred to put default parameters last unless you have pretty good reason not to.
- If your snippet's function takes variadic arguments, use `..args` (although in certain cases, it might be needed to use a different name).
- If your snippet function's body is a single statement, omit the `return` keyword and use an expression instead.

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## Table of Contents
### Array
* [Array concatenation](#array-concatenation)
* [Array difference](#array-difference)
* [Array includes](#array-includes)
* [Array intersection](#array-intersection)
* [Array pull (mutates array)](#array-pull-mutates-array)
* [Array remove](#array-remove)
* [Array sample](#array-sample)
* [Array symmetric difference](#array-symmetric-difference)
* [Array union](#array-union)
* [Array without](#array-without)
* [Array zip](#array-zip)
@ -25,7 +25,6 @@
* [Count occurrences of a value in array](#count-occurrences-of-a-value-in-array)
* [Deep flatten array](#deep-flatten-array)
* [Drop elements in array](#drop-elements-in-array)
* [Fill array](#fill-array)
* [Filter out non unique values in an array](#filter-out-non-unique-values-in-an-array)
* [Flatten array up to depth](#flatten-array-up-to-depth)
* [Flatten array](#flatten-array)
@ -58,12 +57,15 @@
* [Scroll to top](#scroll-to-top)
### Date
* [Convert to english date](#convert-to-english-date)
* [Get days difference between dates](#get-days-difference-between-dates)
* [JSON to date](#json-to-date)
### Function
* [Chain asynchronous functions](#chain-asynchronous-functions)
* [Compose functions](#compose-functions)
* [Curry](#curry)
* [Log function name](#log-function-name)
* [Pipe functions](#pipe-functions)
* [Promisify](#promisify)
* [Run promises in series](#run-promises-in-series)
@ -78,8 +80,11 @@
* [Fibonacci array generator](#fibonacci-array-generator)
* [Greatest common divisor (GCD)](#greatest-common-divisor-gcd)
* [Hamming distance](#hamming-distance)
* [Least common multiple (LCM)](#least-common-multiple-lcm)
* [Percentile](#percentile)
* [Powerset](#powerset)
* [Random integer in range](#random-integer-in-range)
* [Random number in range](#random-number-in-range)
* [Round number to n digits](#round-number-to-n-digits)
* [Standard deviation](#standard-deviation)
@ -101,6 +106,8 @@
* [Capitalize first letter of every word](#capitalize-first-letter-of-every-word)
* [Capitalize first letter](#capitalize-first-letter)
* [Check for palindrome](#check-for-palindrome)
* [Convert string from camelcase](#convert-string-from-camelcase)
* [Convert string to camelcase](#convert-string-to-camelcase)
* [Reverse a string](#reverse-a-string)
* [Sort characters in string (alphabetical)](#sort-characters-in-string-alphabetical)
* [Truncate a string](#truncate-a-string)
@ -119,48 +126,21 @@
* [Measure time taken by function](#measure-time-taken-by-function)
* [Number to array of digits](#number-to-array-of-digits)
* [Ordinal suffix of number](#ordinal-suffix-of-number)
* [Random integer in range](#random-integer-in-range)
* [Random number in range](#random-number-in-range)
* [RGB to hexadecimal](#rgb-to-hexadecimal)
* [URL parameters](#url-parameters)
* [UUID generator](#uuid-generator)
* [Validate email](#validate-email)
* [Validate number](#validate-number)
* [Value or default](#value-or-default)
## Array
### Array concatenation
Use Array spread operators (`...`) to concatenate an array with any additional arrays and/or values, specified in `args`.
```js
const ArrayConcat = (arr, ...args) => [...arr,...args];
// ArrayConcat([1], [1, 2, 3, [4]]) -> [1, 1, 2, 3, [4]]
```
[⬆ back to top](#table-of-contents)
### Array difference
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([1,2,3], [1,2]) -> [3]
```
[⬆ back to top](#table-of-contents)
### Array includes
Use `slice()` to offset the array/string and `indexOf()` to check if the value is included.
Omit the last argument, `fromIndex`, to check the whole array/string.
```js
const includes = (collection, val, fromIndex=0) => collection.slice(fromIndex).indexOf(val) != -1;
// includes("30-seconds-of-code", "code") -> true
// includes([1, 2, 3, 4], [1, 2], 1) -> false
// difference([1,2,3], [1,2,4]) -> [3]
```
[⬆ back to top](#table-of-contents)
@ -176,6 +156,23 @@ const intersection = (a, b) => { const s = new Set(b); return a.filter(x => s.ha
[⬆ back to top](#table-of-contents)
### Array pull (mutates array)
Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed.
Use `Array.length = 0` to mutate the passed in array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values.
```js
const pull = (arr, ...args) => {
let pulled = arr.filter((v, i) => !args.includes(v));
arr.length = 0; pulled.forEach(v => arr.push(v));
};
// let myArray = ['a', 'b', 'c', 'a', 'b', 'c'];
// pull(myArray, 'a', 'c');
// console.log(myArray) -> [ 'b', 'b' ]
```
[⬆ back to top](#table-of-contents)
### Array remove
Use `Array.filter()` to find array elements that return truthy values and `Array.reduce()` to remove elements using `Array.splice()`.
@ -187,7 +184,7 @@ const remove = (arr, func) =>
arr.splice(arr.indexOf(val), 1); return acc.concat(val);
}, [])
: [];
//remove([1, 2, 3, 4], n => n % 2 == 0) -> [2, 4]
// remove([1, 2, 3, 4], n => n % 2 == 0) -> [2, 4]
```
[⬆ back to top](#table-of-contents)
@ -204,6 +201,20 @@ const sample = arr => arr[Math.floor(Math.random() * arr.length)];
[⬆ back to top](#table-of-contents)
### Array symmetric difference
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([1,2,3], [1,2,4]) -> [3,4]
```
[⬆ back to top](#table-of-contents)
### Array union
Create a `Set` with all values of `a` and `b` and convert to an array.
@ -276,7 +287,7 @@ const chunk = (arr, size) =>
Use `Array.filter()` to filter out falsey values (`false`, `null`, `0`, `""`, `undefined`, and `NaN`).
```js
const compact = (arr) => arr.filter(v => v);
const compact = (arr) => arr.filter(Boolean);
// compact([0, 1, false, 2, '', 3, 'a', 'e'*23, NaN, 's', 34]) -> [ 1, 2, 3, 'a', 's', 34 ]
```
@ -321,19 +332,6 @@ const dropElements = (arr, func) => {
[⬆ back to top](#table-of-contents)
### Fill array
Use `Array.map()` to map values between `start` (inclusive) and `end` (exclusive) to `value`.
Omit `start` to start at the first element and/or `end` to finish at the last.
```js
const fillArray = (arr, value, start = 0, end = arr.length) =>
arr.map((v, i) => i >= start && i < end ? value : v);
// fillArray([1,2,3,4],'8',1,3) -> [1,'8','8',4]
```
[⬆ back to top](#table-of-contents)
### Filter out non-unique values in an array
Use `Array.filter()` for an array containing only the unique values.
@ -458,10 +456,10 @@ const initializeArray = (n, value = 0) => Array(n).fill(value);
### Last of list
Use `arr.slice(-1)[0]` to get the last element of the given array.
Use `arr.length - 1` to compute index of the last element of the given array and returning it.
```js
const last = arr => arr.slice(-1)[0];
const last = arr => arr[arr.length - 1];
// last([1,2,3]) -> 3
```
@ -607,7 +605,7 @@ const unique = arr => [...new Set(arr)];
Use `scrollY`, `scrollHeight` and `clientHeight` to determine if the bottom of the page is visible.
```js
const bottomVisible = _ =>
const bottomVisible = () =>
document.documentElement.clientHeight + window.scrollY >= document.documentElement.scrollHeight || document.documentElement.clientHeight;
// bottomVisible() -> true
```
@ -619,7 +617,7 @@ const bottomVisible = _ =>
Use `window.location.href` to get current URL.
```js
const currentUrl = _ => window.location.href;
const currentUrl = () => window.location.href;
// currentUrl() -> 'https://google.com'
```
@ -680,7 +678,7 @@ Get distance from top using `document.documentElement.scrollTop` or `document.bo
Scroll by a fraction of the distance from top. Use `window.requestAnimationFrame()` to animate the scrolling.
```js
const scrollToTop = _ => {
const scrollToTop = () => {
const c = document.documentElement.scrollTop || document.body.scrollTop;
if (c > 0) {
window.requestAnimationFrame(scrollToTop);
@ -693,6 +691,19 @@ const scrollToTop = _ => {
[⬆ back to top](#table-of-contents)
## Date
### Convert to English date
Use `Date.toISOString()`, `split('T')` and `replace()` to convert a date from American format to 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){return}};
// toEnglishDate('09/21/2010') -> '21/09/2010'
```
[⬆ back to top](#table-of-contents)
### Get days difference between dates
Calculate the difference (in days) between to `Date` objects.
@ -702,6 +713,20 @@ const getDaysDiffBetweenDates = (dateInitial, dateFinal) => (dateFinal - dateIni
// getDaysDiffBetweenDates(new Date("2017-12-13"), new Date("2017-12-22")) -> 9
```
[⬆ back to top](#table-of-contents)
### JSON to 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() }`
};
// jsonToDate(/Date(1489525200000)/) -> "14/3/2017"
```
[⬆ back to top](#table-of-contents)
## Function
@ -736,6 +761,7 @@ const multiplyAndAdd5 = compose(add5, multiply)
multiplyAndAdd5(5, 2) -> 15
*/
```
[⬆ back to top](#table-of-contents)
### Curry
@ -756,6 +782,17 @@ const curry = (fn, arity = fn.length, ...args) =>
[⬆ back to top](#table-of-contents)
### Log function name
Use `console.debug()` and the `name` property of the passed method to log the method's name to the `debug` channel of the console.
```js
const functionName = fn => (console.debug(fn.name), fn);
// functionName(Math.max) -> max (logged in debug channel of console)
```
[⬆ back to top](#table-of-contents)
### Pipe functions
Use `Array.reduce()` with the spread operator (`...`) to perform left-to-right function composition.
@ -874,9 +911,12 @@ const isEven = num => num % 2 === 0;
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 <= 1 ? 1 : n * factorial(n - 1);
const factorial = n =>
n < 0 ? (() => { throw new TypeError('Negative numbers are not allowed!') })()
: n <= 1 ? 1 : n * factorial(n - 1);
// factorial(6) -> 720
```
@ -921,6 +961,21 @@ const hammingDistance = (num1, num2) =>
[⬆ back to top](#table-of-contents)
### Least common multiple (LCM)
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));
};
// lcm(12,7) -> 84
```
[⬆ back to top](#table-of-contents)
### Percentile
Use `Array.reduce()` to calculate how many numbers are below the value and how many are the same value and
@ -946,6 +1001,28 @@ const powerset = arr =>
[⬆ back to top](#table-of-contents)
### Random integer in range
Use `Math.random()` to generate a random number and map it to the desired range, using `Math.floor()` to make it an integer.
```js
const randomIntegerInRange = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min;
// randomIntegerInRange(0, 5) -> 2
```
[⬆ back to top](#table-of-contents)
### Random number in range
Use `Math.random()` to generate a random value, map it to the desired range using multiplication.
```js
const randomInRange = (min, max) => Math.random() * (max - min) + min;
// randomInRange(2,10) -> 6.0211363285087005
```
[⬆ back to top](#table-of-contents)
### Round number to n digits
Use `Math.round()` and template literals to round the number to the specified number of digits.
@ -981,7 +1058,7 @@ const standardDeviation = (arr, usePopulation = false) => {
### Speech synthesis (experimental)
Use `SpeechSynthesisUtterance.voice` and `indow.speechSynthesis.getVoices()` to convert a message to speech.
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).
@ -1153,6 +1230,37 @@ const palindrome = str => {
[⬆ back to top](#table-of-contents)
### Convert string from camelcase
Use `replace()` to remove underscores, hyphens and spaces and convert words to camelcase.
Omit the scond argument to use a default separator of '_'.
```js
const fromCamelCase = (str, separator = '_') =>
str.replace(/([a-z\d])([A-Z])/g, '$1' + separator + '$2')
.replace(/([A-Z]+)([A-Z][a-z\d]+)/g, '$1' + separator + '$2').toLowerCase();
// fromCamelCase('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)
### Convert string to camelcase
Use `replace()` to remove underscores, hyphens and spaces and convert words to camelcase.
```js
const toCamelCase = str =>
str.replace(/^([A-Z])|[\s-_]+(\w)/g, (match, p1, p2, offset) => p2 ? p2.toUpperCase() : p1.toLowerCase());
// 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)
### Reverse a string
Use array destructuring and `Array.reverse()` to reverse the order of the characters in the string.
@ -1193,12 +1301,11 @@ const truncate = (str, num) =>
### 3-digit hexcode to 6-digit hexcode
Use `Array.map()`, `split()` and `Array.join()` to join the mapped array for converting a three-digit RGB notated hexadecimal colorcode to the six-digit form.
Use `Array.map()`, `split()` and `Array.join()` to join the mapped array for converting a three-digit RGB notated hexadecimal color-code to the six-digit form.
`Array.slice()` is used to remove `#` from string start since it's added once.
```js
const convertHex = shortHex =>
shortHex[0] == '#' ? ('#' + shortHex.slice(1).split('').map(x => x+x).join('')) :
('#' + shortHex.split('').map(x => x+x).join(''));
'#' + shortHex.slice(shortHex.startsWith('#') ? 1 : 0).split().map(x => x+x).join()
// convertHex('#03f') -> '#0033ff'
// convertHex('05a') -> '#0055aa'
```
@ -1230,11 +1337,14 @@ const getType = v =>
### Hexcode to RGB
Use `Array.slice()`, `Array.map()` and `match()` to convert a hexadecimal colorcode (prefixed with `#`) to a string with the RGB values.
Use bitwise right-shift operator and mask bits with `&` (and) operator to convert a hexadecimal color code (prefixed with `#`) to a string with the RGB values.
```js
const hexToRgb = hex => `rgb(${hex.slice(1).match(/.{2}/g).map(x => parseInt(x, 16)).join()})`
// hexToRgb('#27ae60') -> 'rgb(39,174,96)'
const hexToRgb = hex => {
const h = parseInt(hex.slice(1), 16);
return `rgb(${h >> 16}, ${(h & 0x00ff00) >> 8}, ${h & 0x0000ff})`;
}
// hexToRgb('#27ae60') -> 'rgb(39, 174, 96)'
```
[⬆ back to top](#table-of-contents)
@ -1330,11 +1440,11 @@ const timeTaken = callback => {
### Number to array of digits
Convert the number to a string, use `split()` to convert build an array.
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).split('').map(i => parseInt(i));
const digitize = n => [...''+n].map(i => parseInt(i));
// digitize(2334) -> [2, 3, 3, 4]
```
@ -1358,28 +1468,6 @@ const toOrdinalSuffix = num => {
[⬆ back to top](#table-of-contents)
### Random integer in range
Use `Math.random()` to generate a random number and map it to the desired range, using `Math.floor()` to make it an integer.
```js
const randomIntegerInRange = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min;
// randomIntegerInRange(0, 5) -> 2
```
[⬆ back to top](#table-of-contents)
### Random number in range
Use `Math.random()` to generate a random value, map it to the desired range using multiplication.
```js
const randomInRange = (min, max) => Math.random() * (max - min) + min;
// randomInRange(2,10) -> 6.0211363285087005
```
[⬆ back to top](#table-of-contents)
### RGB to hexadecimal
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.
@ -1411,7 +1499,7 @@ const getUrlParameters = url =>
Use `crypto` API to generate a UUID, compliant with [RFC4122](https://www.ietf.org/rfc/rfc4122.txt) version 4.
```js
const uuid = _ =>
const uuid = () =>
([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c =>
(c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16)
);
@ -1446,17 +1534,6 @@ const validateNumber = n => !isNaN(parseFloat(n)) && isFinite(n) && Number(n) ==
[⬆ back to top](#table-of-contents)
### Value or default
Returns value, or default value if passed value is `falsy`.
```js
const valueOrDefault = (value, d) => value || d;
// valueOrDefault(NaN, 30) -> 30
```
[⬆ 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/).*

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@ -1,6 +1,7 @@
/*
This is the linter script that lints snippets.
Run using `npm run linter`.
You might have to run `npm i -g semistandard` for this script to run properly.
*/
// Load modules
const fs = require('fs-extra'), cp = require('child_process'), path = require('path'), chalk = require('chalk');

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@ -1,11 +1,10 @@
### 3-digit hexcode to 6-digit hexcode
Use `Array.map()`, `split()` and `Array.join()` to join the mapped array for converting a three-digit RGB notated hexadecimal colorcode to the six-digit form.
Use `Array.map()`, `split()` and `Array.join()` to join the mapped array for converting a three-digit RGB notated hexadecimal color-code to the six-digit form.
`Array.slice()` is used to remove `#` from string start since it's added once.
```js
const convertHex = shortHex =>
shortHex[0] == '#' ? ('#' + shortHex.slice(1).split('').map(x => x+x).join('')) :
('#' + shortHex.split('').map(x => x+x).join(''));
'#' + shortHex.slice(shortHex.startsWith('#') ? 1 : 0).split().map(x => x+x).join()
// convertHex('#03f') -> '#0033ff'
// convertHex('05a') -> '#0055aa'
```

2
snippets/UUID-generator.md
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@ -3,7 +3,7 @@
Use `crypto` API to generate a UUID, compliant with [RFC4122](https://www.ietf.org/rfc/rfc4122.txt) version 4.
```js
const uuid = _ =>
const uuid = () =>
([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c =>
(c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16)
);

8
snippets/array-concatenation.md
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@ -1,8 +0,0 @@
### Array concatenation
Use Array spread operators (`...`) to concatenate an array with any additional arrays and/or values, specified in `args`.
```js
const ArrayConcat = (arr, ...args) => [...arr,...args];
// ArrayConcat([1], [1, 2, 3, [4]]) -> [1, 1, 2, 3, [4]]
```

2
snippets/array-difference.md
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@ -4,5 +4,5 @@ Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values no
```js
const difference = (a, b) => { const s = new Set(b); return a.filter(x => !s.has(x)); };
// difference([1,2,3], [1,2]) -> [3]
// difference([1,2,3], [1,2,4]) -> [3]
```

10
snippets/array-includes.md
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@ -1,10 +0,0 @@
### Array includes
Use `slice()` to offset the array/string and `indexOf()` to check if the value is included.
Omit the last argument, `fromIndex`, to check the whole array/string.
```js
const includes = (collection, val, fromIndex=0) => collection.slice(fromIndex).indexOf(val) != -1;
// includes("30-seconds-of-code", "code") -> true
// includes([1, 2, 3, 4], [1, 2], 1) -> false
```

14
snippets/array-pull-(mutates-array).md Normal file
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@ -0,0 +1,14 @@
### Array pull (mutates array)
Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed.
Use `Array.length = 0` to mutate the passed in array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values.
```js
const pull = (arr, ...args) => {
let pulled = arr.filter((v, i) => !args.includes(v));
arr.length = 0; pulled.forEach(v => arr.push(v));
};
// let myArray = ['a', 'b', 'c', 'a', 'b', 'c'];
// pull(myArray, 'a', 'c');
// console.log(myArray) -> [ 'b', 'b' ]
```

2
snippets/array-remove.md
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@ -9,5 +9,5 @@ const remove = (arr, func) =>
arr.splice(arr.indexOf(val), 1); return acc.concat(val);
}, [])
: [];
//remove([1, 2, 3, 4], n => n % 2 == 0) -> [2, 4]
// remove([1, 2, 3, 4], n => n % 2 == 0) -> [2, 4]
```

11
snippets/array-symmetric-difference.md Normal file
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@ -0,0 +1,11 @@
### Array symmetric difference
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([1,2,3], [1,2,4]) -> [3,4]
```

2
snippets/bottom-visible.md
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@ -3,7 +3,7 @@
Use `scrollY`, `scrollHeight` and `clientHeight` to determine if the bottom of the page is visible.
```js
const bottomVisible = _ =>
const bottomVisible = () =>
document.documentElement.clientHeight + window.scrollY >= document.documentElement.scrollHeight || document.documentElement.clientHeight;
// bottomVisible() -> true
```

2
snippets/compact.md
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@ -3,6 +3,6 @@
Use `Array.filter()` to filter out falsey values (`false`, `null`, `0`, `""`, `undefined`, and `NaN`).
```js
const compact = (arr) => arr.filter(v => v);
const compact = (arr) => arr.filter(Boolean);
// compact([0, 1, false, 2, '', 3, 'a', 'e'*23, NaN, 's', 34]) -> [ 1, 2, 3, 'a', 's', 34 ]
```

2
snippets/compose-functions.md
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@ -11,4 +11,4 @@ const multiply = (x, y) => x * y
const multiplyAndAdd5 = compose(add5, multiply)
multiplyAndAdd5(5, 2) -> 15
*/
```
```

13
snippets/convert-string-from-camelcase.md Normal file
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@ -0,0 +1,13 @@
### Convert string from camelcase
Use `replace()` to remove underscores, hyphens and spaces and convert words to camelcase.
Omit the scond argument to use a default separator of '_'.
```js
const fromCamelCase = (str, separator = '_') =>
str.replace(/([a-z\d])([A-Z])/g, '$1' + separator + '$2')
.replace(/([A-Z]+)([A-Z][a-z\d]+)/g, '$1' + separator + '$2').toLowerCase();
// fromCamelCase('someDatabaseFieldName', ' ') -> 'some database field name'
// fromCamelCase('someLabelThatNeedsToBeCamelized', '-') -> 'some-label-that-needs-to-be-camelized'
// fromCamelCase('someJavascriptProperty', '_') -> 'some_javascript_property'
```

12
snippets/convert-string-to-camelcase.md Normal file
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@ -0,0 +1,12 @@
### Convert string to camelcase
Use `replace()` to remove underscores, hyphens and spaces and convert words to camelcase.
```js
const toCamelCase = str =>
str.replace(/^([A-Z])|[\s-_]+(\w)/g, (match, p1, p2, offset) => p2 ? p2.toUpperCase() : p1.toLowerCase());
// 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'
```

10
snippets/convert-to-english-date.md Normal file
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@ -0,0 +1,10 @@
### Convert to English date
Use `Date.toISOString()`, `split('T')` and `replace()` to convert a date from American format to 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){return}};
// toEnglishDate('09/21/2010') -> '21/09/2010'
```

2
snippets/current-URL.md
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@ -3,6 +3,6 @@
Use `window.location.href` to get current URL.
```js
const currentUrl = _ => window.location.href;
const currentUrl = () => window.location.href;
// currentUrl() -> 'https://google.com'
```

5
snippets/factorial.md
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@ -3,8 +3,11 @@
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 <= 1 ? 1 : n * factorial(n - 1);
const factorial = n =>
n < 0 ? (() => { throw new TypeError('Negative numbers are not allowed!') })()
: n <= 1 ? 1 : n * factorial(n - 1);
// factorial(6) -> 720
```

10
snippets/fill-array.md
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@ -1,10 +0,0 @@
### Fill array
Use `Array.map()` to map values between `start` (inclusive) and `end` (exclusive) to `value`.
Omit `start` to start at the first element and/or `end` to finish at the last.
```js
const fillArray = (arr, value, start = 0, end = arr.length) =>
arr.map((v, i) => i >= start && i < end ? value : v);
// fillArray([1,2,3,4],'8',1,3) -> [1,'8','8',4]
```

9
snippets/hexcode-to-RGB.md
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@ -1,8 +1,11 @@
### Hexcode to RGB
Use `Array.slice()`, `Array.map()` and `match()` to convert a hexadecimal colorcode (prefixed with `#`) to a string with the RGB values.
Use bitwise right-shift operator and mask bits with `&` (and) operator to convert a hexadecimal color code (prefixed with `#`) to a string with the RGB values.
```js
const hexToRgb = hex => `rgb(${hex.slice(1).match(/.{2}/g).map(x => parseInt(x, 16)).join()})`
// hexToRgb('#27ae60') -> 'rgb(39,174,96)'
const hexToRgb = hex => {
const h = parseInt(hex.slice(1), 16);
return `rgb(${h >> 16}, ${(h & 0x00ff00) >> 8}, ${h & 0x0000ff})`;
}
// hexToRgb('#27ae60') -> 'rgb(39, 174, 96)'
```

4
snippets/last-of-list.md
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@ -1,8 +1,8 @@
### Last of list
Use `arr.slice(-1)[0]` to get the last element of the given array.
Use `arr.length - 1` to compute index of the last element of the given array and returning it.
```js
const last = arr => arr.slice(-1)[0];
const last = arr => arr[arr.length - 1];
// last([1,2,3]) -> 3
```

12
snippets/least-common-multiple-(LCM).md Normal file
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@ -0,0 +1,12 @@
### Least common multiple (LCM)
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));
};
// lcm(12,7) -> 84
```

8
snippets/log-function-name.md Normal file
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@ -0,0 +1,8 @@
### Log function name
Use `console.debug()` and the `name` property of the passed method to log the method's name to the `debug` channel of the console.
```js
const functionName = fn => (console.debug(fn.name), fn);
// functionName(Math.max) -> max (logged in debug channel of console)
```

4
snippets/number-to-array-of-digits.md
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@ -1,9 +1,9 @@
### Number to array of digits
Convert the number to a string, use `split()` to convert build an array.
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).split('').map(i => parseInt(i));
const digitize = n => [...''+n].map(i => parseInt(i));
// digitize(2334) -> [2, 3, 3, 4]
```

2
snippets/scroll-to-top.md
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@ -4,7 +4,7 @@ Get distance from top using `document.documentElement.scrollTop` or `document.bo
Scroll by a fraction of the distance from top. Use `window.requestAnimationFrame()` to animate the scrolling.
```js
const scrollToTop = _ => {
const scrollToTop = () => {
const c = document.documentElement.scrollTop || document.body.scrollTop;
if (c > 0) {
window.requestAnimationFrame(scrollToTop);

2
snippets/speech-synthesis-(experimental).md
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@ -1,6 +1,6 @@
### Speech synthesis (experimental)
Use `SpeechSynthesisUtterance.voice` and `indow.speechSynthesis.getVoices()` to convert a message to speech.
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).

8
snippets/value-or-default.md
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@ -1,8 +0,0 @@
### Value or default
Returns value, or default value if passed value is `falsy`.
```js
const valueOrDefault = (value, d) => value || d;
// valueOrDefault(NaN, 30) -> 30
```

16
tag_database
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@ -1,11 +1,11 @@
3-digit-hexcode-to-6-digit-hexcode:utility
anagrams-of-string-(with-duplicates):string
array-concatenation:array
array-difference:array
array-includes:array
array-intersection:array
array-pull-(mutates-array):array
array-remove:array
array-sample:array
array-symmetric-difference:array
array-union:array
array-without:array
array-zip:array
@ -20,6 +20,9 @@ clean-JSON-object:object
collatz-algorithm:math
compact:array
compose-functions:function
convert-string-from-camelcase:string
convert-string-to-camelcase:string
convert-to-english-date:date
count-occurrences-of-a-value-in-array:array
current-URL:browser
curry:function
@ -32,7 +35,6 @@ escape-regular-expression:utility
even-or-odd-number:math
factorial:math
fibonacci-array-generator:math
fill-array:array
filter-out-non-unique-values-in-an-array:array
flatten-array-up-to-depth:array
flatten-array:array
@ -55,7 +57,10 @@ is-function:utility
is-number:utility
is-string:utility
is-symbol:utility
JSON-to-date:date
last-of-list:array
least-common-multiple-(LCM):math
log-function-name:function
measure-time-taken-by-function:utility
median-of-array-of-numbers:array
nth-element-of-array:array
@ -68,8 +73,8 @@ pick:array
pipe-functions:function
powerset:math
promisify:function
random-integer-in-range:utility
random-number-in-range:utility
random-integer-in-range:math
random-number-in-range:math
read-file-as-array-of-lines:node
redirect-to-URL:browser
reverse-a-string:string
@ -95,5 +100,4 @@ URL-parameters:utility
UUID-generator:utility
validate-email:utility
validate-number:utility
value-or-default:utility
write-JSON-to-file:node