https://github.com/angus-c/just

A library of dependency-free JavaScript utilities that do just one thing.
https://github.com/angus-c/just

dependency-free javascript library pwa tiny typescript utilities utils

Last synced: 4 days ago
JSON representation

A library of dependency-free JavaScript utilities that do just one thing.

• Host: GitHub
• URL: https://github.com/angus-c/just
• Owner: angus-c
• License: mit
• Created: 2016-06-26T02:04:54.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2024-02-11T12:23:37.000Z (10 months ago)
• Last Synced: 2024-12-09T05:43:02.129Z (4 days ago)
• Topics: dependency-free, javascript, library, pwa, tiny, typescript, utilities, utils
• Language: JavaScript
• Homepage: https://anguscroll.com/just
• Size: 21.8 MB
• Stars: 6,073
• Watchers: 42
• Forks: 209
• Open Issues: 52
• Metadata Files:
  • Readme: README.md
  • Contributing: CONTRIBUTING.md
  • License: LICENSE
  • Code of conduct: CODE_OF_CONDUCT.md
  • Security: SECURITY.md

Awesome Lists containing this project

• awesome - angus-c/just - A library of dependency-free JavaScript utilities that do just one thing. (JavaScript)
• awesome-tiny-js - just - 82 helpers in separate packages [(list).](https://anguscroll.com/just/) (Generic Utilities / Reactive Programming)
• awesome - angus-c/just - A library of dependency-free JavaScript utilities that do just one thing. (JavaScript)
• awesome-list - just - free JavaScript functions that do just do one thing. | angus-c | 2885 | (JavaScript)
• awesome-starred - angus-c/just - A library of dependency-free JavaScript utilities that do just one thing. (typescript)

README

        


# Just

## [Docs](#the-modules-package) | [Why?](#read-books) | [Try It](https://anguscroll.com/just) | [Contribute!](https://github.com/angus-c/just/blob/master/CONTRIBUTING.md)

A library of **zero-dependency** npm modules that do just one thing.

A guilt-free alternative to those bulkier utility libraries. Ideal for PWA development or whenever bytes are precious.

![Build status](https://github.com/angus-c/just/actions/workflows/node.js.yml/badge.svg)

We welcome contributions. Please follow our [contribution guidelines](https://github.com/angus-c/just/blob/master/CONTRIBUTING.md).

## Try :icecream:

A [REPL](https://anguscroll.com/just) for every utility (powered by [RunKit](https://runkit.com))



## Read :books:

- [TRADEOFFS.md](https://github.com/angus-c/just/blob/master/TRADEOFFS.md) -- When to use Just (and when not to).

- [The Zen of Dependency-Free](https://medium.com/@angustweets/just-a12d54221f65#.ljib0mfr5) -- Why I wrote Just.

## ES and CJS modules available for every utility  

All packages support ES module or Common JS syntax without requiring transpilation

```

// esm (node / bundler)

import clone from 'just-clone';

// esm (native browser code)

import clone from './node_modules/just-clone/index.mjs';

// cjs

const clone = require('just-clone');

```

## TypeScript 

We've now added TypeScript definitions and tests for every Just utility

## Browser/Platform Support :computer:

Most utilities still work with any platform that supports ES5, but these are the earliest versions guranteed to support _every_ utility. For guidance, any platform that supports [spread in array literals](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax#spread_in_array_literals) will work with Just.

| Chrome | Safari | Firefox | Edge | Node | Mobile Safari | Android Chrome      |

| ------ | ------ | ------- | ---- | ---- | ------------- | ------------- |

| 46    | 8    | 16     | 12   | 6.0   | 8        | 46 |

## The Modules :package:

- [Collections](#collections) {}[]

  - [just-diff](#just-diff)

  - [just-diff-apply](#just-diff-apply)

  - [just-compare](#just-compare)

  - [just-clone](#just-clone)

  - [just-pluck-it](#just-pluck-it)

  - [just-flush](#just-flush)

- [Objects](#objects) {}

  - [just-extend](#just-extend)

  - [just-merge](#just-merge)

  - [just-values](#just-values)

  - [just-entries](#just-entries)

  - [just-pick](#just-pick)

  - [just-omit](#just-omit)

  - [just-filter-object](#just-filter-object)

  - [just-map-object](#just-map-object)

  - [just-map-values](#just-map-values)

  - [just-map-keys](#just-map-keys)

  - [just-deep-map-values](#just-deep-map-values)

  - [just-reduce-object](#just-reduce-object)

  - [just-is-empty](#just-is-empty)

  - [just-is-circular](#just-is-circular)

  - [just-is-primitive](#just-is-primitive)

  - [just-safe-get](#just-safe-get)

  - [just-safe-set](#just-safe-set)

  - [just-typeof](#just-typeof)

  - [just-flip-object](#just-flip-object)

  - [just-has](#just-has)

- [Arrays](#arrays) []

  - [just-cartesian-product](#just-cartesian-product)

  - [just-unique](#just-unique)

  - [just-flatten-it](#just-flatten-it)

  - [just-index](#just-index)

  - [just-insert](#just-insert)

  - [just-intersect](#just-intersect)

  - [just-compact](#just-compact)

  - [just-last](#just-last)

  - [just-tail](#just-tail)

  - [just-random](#just-random)

  - [just-shuffle](#just-shuffle)

  - [just-split](#just-split)

  - [just-split-at](#just-split-at)

  - [just-order-by](#just-order-by)

  - [just-sort-by](#just-sort-by)

  - [just-partition](#just-partition)

  - [just-permutations](#just-permutations)

  - [just-range](#just-range)

  - [just-remove](#just-remove)

  - [just-union](#just-union)

  - [just-zip-it](#just-zip-it)

  - [just-group-by](#just-group-by)

- [Statistics](#stats) Σ

  - [just-mean](#just-mean)

  - [just-median](#just-median)

  - [just-mode](#just-mode)

  - [just-percentile](#just-percentile)

  - [just-variance](#just-variance)

  - [just-standard-deviation](#just-standard-deviation)

  - [just-skewness](#just-skewness)

- [Strings](#strings) ""

  - [just-template](#just-template)

  - [just-truncate](#just-truncate)

  - [just-prune](#just-prune)

  - [just-squash](#just-squash)

  - [just-left-pad](#just-left-pad)

  - [just-right-pad](#just-right-pad)

  - [just-camel-case](#just-camel-case)

  - [just-kebab-case](#just-kebab-case)

  - [just-snake-case](#just-snake-case)

  - [just-pascal-case](#just-pascal-case)

  - [just-capitalize](#just-capitalize)

  - [just-replace-all](#just-replace-all)

- [Numbers](#numbers) +-

  - [just-clamp](#just-clamp)

  - [just-is-prime](#just-is-prime)

  - [just-modulo](#just-modulo)

  - [just-random-integer](#just-random-integer)

- [Functions](#functions) =>

  - [just-compose](#just-compose)

  - [just-curry-it](#just-curry-it)

  - [just-demethodize](#just-demethodize)

  - [just-flip](#just-flip)

  - [just-partial-it](#just-partial-it)

  - [just-pipe](#just-pipe)

  - [just-debounce-it](#just-debounce-it)

  - [just-memoize](#just-memoize)

  - [just-memoize-last](#just-memoize-last)

  - [just-random](#just-random)

  - [just-throttle](#just-throttle)

  - [just-once](#just-once)

### Collections

### [just-diff](https://www.npmjs.com/package/just-diff)

[source](https://github.com/angus-c/just/tree/master/packages/collection-diff)

[`🍦 Try it`](https://anguscroll.com/just/just-diff)

```shell

npm install just-diff

```

```shell

yarn add just-diff

```

Return an object representing the difference between two other objects

Pass converter to format as http://jsonpatch.com

```js

import {diff} from 'just-diff';

const obj1 = {a: 4, b: 5};

const obj2 = {a: 3, b: 5};

const obj3 = {a: 4, c: 5};

diff(obj1, obj2);

[

  { "op": "replace", "path": ['a'], "value": 3 }

]

diff(obj2, obj3);

[

  { "op": "remove", "path": ['b'] },

  { "op": "replace", "path": ['a'], "value": 4 }

  { "op": "add", "path": ['c'], "value": 5 }

]

// using converter to generate jsPatch standard paths

import {diff, jsonPatchPathConverter} from 'just-diff'

diff(obj1, obj2, jsonPatchPathConverter);

[

  { "op": "replace", "path": '/a', "value": 3 }

]

diff(obj2, obj3, jsonPatchPathConverter);

[

  { "op": "remove", "path": '/b' },

  { "op": "replace", "path": '/a', "value": 4 }

  { "op": "add", "path": '/c', "value": 5 }

]

// arrays

const obj4 = {a: 4, b: [1, 2, 3]};

const obj5 = {a: 3, b: [1, 2, 4]};

const obj6 = {a: 3, b: [1, 2, 4, 5]};

diff(obj4, obj5);

[

  { "op": "replace", "path": ['a'], "value": 3 }

  { "op": "replace", "path": ['b', 2], "value": 4 }

]

diff(obj5, obj6);

[

  { "op": "add", "path": ['b', 3], "value": 5 }

]

// nested paths

const obj7 = {a: 4, b: {c: 3}};

const obj8 = {a: 4, b: {c: 4}};

const obj9 = {a: 5, b: {d: 4}};

diff(obj7, obj8);

[

  { "op": "replace", "path": ['b', 'c'], "value": 4 }

]

diff(obj8, obj9);

[

  { "op": "replace", "path": ['a'], "value": 5 }

  { "op": "remove", "path": ['b', 'c']}

  { "op": "add", "path": ['b', 'd'], "value": 4 }

]

```

### [just-diff-apply](https://www.npmjs.com/package/just-diff-apply)

[source](https://github.com/angus-c/just/tree/master/packages/collection-diff-apply)

[`🍦 Try it`](https://anguscroll.com/just/just-diff-apply)

```shell

npm install just-diff-apply

```

```shell

yarn add just-diff-apply

```

Apply a diff object to an object. Pass converter to apply a http://jsonpatch.com standard patch

```js

  import {diffApply} from 'just-diff-apply';

  const obj1 = {a: 3, b: 5};

  diffApply(obj1,

    [

      { "op": "remove", "path": ['b'] },

      { "op": "replace", "path": ['a'], "value": 4 },

      { "op": "add", "path": ['c'], "value": 5 }

    ]

  );

  obj1; // {a: 4, c: 5}

  const obj2 = {a: 3, b: 5};

  diffApply(obj2,

    [

      { "op": "move", "from": ['a'], "path": ['c']},

    ]

  );

  obj2; // {b: 5, c: 3}

  // using converter to apply jsPatch standard paths

  // see http://jsonpatch.com

  import {diffApply, jsonPatchPathConverter} from 'just-diff-apply'

  const obj3 = {a: 3, b: 5};

  diffApply(obj3, [

    { "op": "remove", "path": '/b' },

    { "op": "replace", "path": '/a', "value": 4 }

    { "op": "add", "path": '/c', "value": 5 }

  ], jsonPatchPathConverter);

  obj3; // {a: 4, c: 5}

  // arrays (array key can be string or numeric)

  const obj4 = {a: 4, b: [1, 2, 3]};

  diffApply(obj4, [

    { "op": "replace", "path": ['a'], "value": 3 }

    { "op": "replace", "path": ['b', 2], "value": 4 }

    { "op": "add", "path": ['b', 3], "value": 9 }

  ]);

  obj4; // {a: 3, b: [1, 2, 4, 9]}

  // nested paths

  const obj5 = {a: 4, b: {c: 3}};

  diffApply(obj5, [

    { "op": "replace", "path": ['a'], "value": 5 }

    { "op": "remove", "path": ['b', 'c']}

    { "op": "add", "path": ['b', 'd'], "value": 4 }

  ]);

  obj5; // {a: 5, b: {d: 4}}

```

### [just-compare](https://www.npmjs.com/package/just-compare)

[source](https://github.com/angus-c/just/tree/master/packages/collection-compare)

[`🍦 Try it`](https://anguscroll.com/just/just-compare)

```shell

npm install just-compare

```

```shell

yarn add just-compare

```

Compare two collections

```js

import compare from 'just-compare';

// primitives: value1 === value2

// functions: value1.toString == value2.toString

// arrays: if length, sequence and values of properties are identical

// objects: if length, names and values of properties are identical

compare([1, [2, 3]], [1, [2, 3]]); // true

compare([1, [2, 3], 4], [1, [2, 3]]); // false

compare({a: 2, b: 3}, {a: 2, b: 3}); // true

compare({a: 2, b: 3}, {b: 3, a: 2}); // true

compare({a: 2, b: 3, c: 4}, {a: 2, b: 3}); // false

compare({a: 2, b: 3}, {a: 2, b: 3, c: 4}); // false

compare([1, [2, {a: 4}], 4], [1, [2, {a: 4}]]); // false

compare([1, [2, {a: 4}], 4], [1, [2, {a: 4}], 4]); // true

compare(NaN, NaN); // true

```

### [just-clone](https://www.npmjs.com/package/just-clone)

[source](https://github.com/angus-c/just/tree/master/packages/collection-clone)

[`🍦 Try it`](https://anguscroll.com/just/just-clone)

```shell

npm install just-clone

```

```shell

yarn add just-clone

```

Deep copies objects, arrays, maps and sets

```js

// Deep copies objects and arrays, doesn't clone functions

import clone from 'just-clone';

var arr = [1, 2, 3];

var subObj = { aa: 1 };

var obj = { a: 3, b: 5, c: arr, d: subObj };

var objClone = clone(obj);

arr.push(4);

objClone.d.bb = 2;

obj; // {a: 3, b: 5, c: [1, 2, 3, 4], d: {aa: 1}}

objClone; // {a: 3, b: 5, c: [1, 2, 3], d: {aa: 1, bb: 2}}

```

### [just-pluck-it](https://www.npmjs.com/package/just-pluck-it)

[source](https://github.com/angus-c/just/tree/master/packages/collection-pluck)

[`🍦 Try it`](https://anguscroll.com/just/just-pluck-it)

```shell

npm install just-pluck-it

```

```shell

yarn add just-pluck-it

```

Pluck a property from each member of a collection

```js

import pluck from 'just-pluck-it';

pluck([{a:1, b:2}, {a:4, b:3}, {a:2, b:5}], 'a'); // [1, 4, 2]

pluck({x: {a:1, b:2}, y: {a:4, b:3}, z: {a:2, b:5}}, 'a'); // {x: 1, y: 4, z: 2}

```

### [just-flush](https://www.npmjs.com/package/just-flush)

[source](https://github.com/angus-c/just/tree/master/packages/collection-flush)

[`🍦 Try it`](https://anguscroll.com/just/just-flush)

```shell

npm install just-flush

```

```shell

yarn add just-flush

```

Returns a copy of an array or object with null/undefined members removed

```js

import flush from 'just-flush';

flush([1, undefined, 2, null, 3, NaN, 0]); // [1, 2, 3, NaN, 0]

flush([true, null, false, true, [null], undefined]); // [true, false, true, [null]]

flush({a: 2, b: null, c: 4, d: undefined}); // {a: 2, c: 4}

flush('something'); // undefined

flush(); // undefined

```

### Objects

### [just-extend](https://www.npmjs.com/package/just-extend)

[source](https://github.com/angus-c/just/tree/master/packages/object-extend)

[`🍦 Try it`](https://anguscroll.com/just/just-extend)

```shell

npm install just-extend

```

```shell

yarn add just-extend

```

Extend an object

```js

import extend from 'just-extend';

var obj = {a: 3, b: 5};

extend(obj, {a: 4, c: 8}); // {a: 4, b: 5, c: 8}

obj; // {a: 4, b: 5, c: 8}

var obj = {a: 3, b: 5};

extend({}, obj, {a: 4, c: 8}); // {a: 4, b: 5, c: 8}

obj; // {a: 3, b: 5}

var arr = [1, 2, 3];

var obj = {a: 3, b: 5};

extend(obj, {c: arr}); // {a: 3, b: 5, c: [1, 2, 3]}

arr.push(4);

obj; // {a: 3, b: 5, c: [1, 2, 3, 4]}

var arr = [1, 2, 3];

var obj = {a: 3, b: 5};

extend(true, obj, {c: arr}); // {a: 3, b: 5, c: [1, 2, 3]}

arr.push(4);

obj; // {a: 3, b: 5, c: [1, 2, 3]}

extend({a: 4, b: 5}); // {a: 4, b: 5}

extend({a: 4, b: 5}, 3); {a: 4, b: 5}

extend({a: 4, b: 5}, true); {a: 4, b: 5}

extend('hello', {a: 4, b: 5}); // throws

extend(3, {a: 4, b: 5}); // throws

```

### [just-merge](https://www.npmjs.com/package/just-merge)

[source](https://github.com/angus-c/just/tree/master/packages/object-merge)

[`🍦 Try it`](https://anguscroll.com/just/just-merge)

```shell

npm install just-merge

```

```shell

yarn add just-merge

```

Shallow assign. Like just-extend but without deep copy option.

```js

import merge from 'just-merge';

let obj = {a: 3, b: 5};

merge(obj, {a: 4, c: 8}); // {a: 4, b: 5, c: 8}

obj; // {a: 4, b: 5, c: 8}

let obj = {a: 3, b: 5};

merge({}, obj, {a: 4, c: 8}); // {a: 4, b: 5, c: 8}

obj; // {a: 3, b: 5}

let arr = [1, 2, 3];

let obj = {a: 3, b: 5};

merge(obj, {c: arr}); // {a: 3, b: 5, c: [1, 2, 3]}

arr.push[4];

obj; // {a: 3, b: 5, c: [1, 2, 3, 4]}

merge({a: 4, b: 5}); // {a: 4, b: 5}

merge(3, {a: 4, b: 5}); // throws

merge({a: 4, b: 5}, 3); // throws

merge({a: 4, b: 5}, {b: 4, c: 5}, 'c'); // throws

```

### [just-values](https://www.npmjs.com/package/just-values)

[source](https://github.com/angus-c/just/tree/master/packages/object-values)

[`🍦 Try it`](https://anguscroll.com/just/just-values)

```shell

npm install just-values

```

```shell

yarn add just-values

```

Return property values as an array

```js

const values = require('just-values');

values({a: 4, c: 8}); // [4, 8]

values({a: {aa: 2}, b: {bb: 4}}); // [{aa: 2}, {bb: 4}]

values({}); // []

values([1, 2, 3]); // [1, 2, 3]

values(function(a, b) {return a + b;}); // []

values(new String('hello')); // ['h', 'e', 'l', 'l', 'o']

values(1); // throws exception

values(true); // throws exception

values(undefined); // throws exception

values(null); // throws exception

```

### [just-entries](https://www.npmjs.com/package/just-entries)

[source](https://github.com/angus-c/just/tree/master/packages/object-entries)

[`🍦 Try it`](https://anguscroll.com/just/just-entries)

```shell

npm install just-entries

```

```shell

yarn add just-entries

```

Return object entries as an array of [key, value] pairs

```js

import entries from 'just-entries';

// Object:

entries({c: 8, a: 4}); // [['c', 8], ['a', 4]]

entries({b: {bb: 4}, a: {aa: 2}}); // [['b', {bb: 4}], ['a', {aa: 2}]]

entries({}); // []

// Array:

entries([{c: 8}, {a: 4}]); // [[0, {c: 8}], [1, {a: 4}]]

entries(['À', 'mauvais', 'ouvrier', 'point', 'de', 'bon', 'outil'])

// [[0, 'À'], [1, 'mauvais'] ... [6, 'outil']]

entries([]); // []

```

### [just-pick](https://www.npmjs.com/package/just-pick)

[source](https://github.com/angus-c/just/tree/master/packages/object-pick)

[`🍦 Try it`](https://anguscroll.com/just/just-pick)

```shell

npm install just-pick

```

```shell

yarn add just-pick

```

Copy an object but with only the specified keys

```js

import pick from 'just-pick';

var obj = { a: 3, b: 5, c: 9 };

pick(obj, ['a', 'c']); // {a: 3, c: 9}

pick(obj, 'a', 'c'); // {a: 3, c: 9}

pick(obj, ['a', 'b', 'd']); // {a: 3, b: 5}

pick(obj, ['a', 'a']); // {a: 3}

```

### [just-omit](https://www.npmjs.com/package/just-omit)

[source](https://github.com/angus-c/just/tree/master/packages/object-omit)

[`🍦 Try it`](https://anguscroll.com/just/just-omit)

```shell

npm install just-omit

```

```shell

yarn add just-omit

```

Copy an object but omit the specified keys

```js

import omit from 'just-omit';

var obj = {a: 3, b: 5, c: 9};

omit(obj, ['a', 'c']); // {b: 5}

omit(obj, 'a', 'c'); // {b: 5}

omit(obj, ['a', 'b', 'd']); // {c: 9}

omit(obj, ['a', 'a']); // {b: 5, c: 9}

```

### [just-is-empty](https://www.npmjs.com/package/just-is-empty)

[source](https://github.com/angus-c/just/tree/master/packages/object-is-empty)

[`🍦 Try it`](https://anguscroll.com/just/just-is-empty)

```shell

npm install just-is-empty

```

```shell

yarn add just-is-empty

```

Return true if object has no enumerable key values

```js

import isEmpty from 'just-is-empty';

 isEmpty({a: 3, b: 5}) // false

 isEmpty([1, 2]) // false

 isEmpty(new Set([1, 2, 2])) // false

 isEmpty((new Map()).set('a', 2)) // false

 isEmpty({}) // true

 isEmpty([]) // true

 isEmpty(new Set()) // true

 isEmpty(new Map()) // true

 isEmpty('abc') // false

 isEmpty('') // true

 isEmpty(0) // true

 isEmpty(1) // true

 isEmpty(true) // true

 isEmpty(Symbol('abc')); // true

 isEmpty(//); // true

 isEmpty(new String('abc')); // false

 isEmpty(new String('')); // true

 isEmpty(new Boolean(true)); // true

 isEmpty(null) // true

 isEmpty(undefined) // true

```

### [just-is-circular](https://www.npmjs.com/package/just-is-circular)

[source](https://github.com/angus-c/just/tree/master/packages/object-is-circular)

[`🍦 Try it`](https://anguscroll.com/just/just-is-circular)

```shell

npm install just-is-circular

```

```shell

yarn add just-is-circular

```

Return true if object has a circular reference

NOTE: not supported in IE or microsoft edge

```js

import isCircular from 'just-is-circular';

const a = {};

a.b = a;

isCircular(a); // true

const a = {};

a.b = {

  c: a

};

isCircular(a); // true

const a = {};

a.b = {

  c: 4

};

isCircular(a); // false

const a = [];

a.push(a);

isCircular(a); // true

isCircular({}); // false

isCircular('hi'); // false

isCircular(undefined); // false

```

### [just-is-primitive](https://www.npmjs.com/package/just-is-primitive)

[source](https://github.com/angus-c/just/tree/master/packages/object-is-primitive)

[`🍦 Try it`](https://anguscroll.com/just/just-is-primitive)

```shell

npm install just-is-primitive

```

```shell

yarn add just-is-primitive

```

Determine if a value is a primitive value

```js

import isPrimitive from 'just-is-primitive';

isPrimitive('hi') // true

isPrimitive(3) // true

isPrimitive(true) // true

isPrimitive(false) // true

isPrimitive(null) // true

isPrimitive(undefined) // true

isPrimitive(Symbol()) // true

isPrimitive({}) // false

isPrimitive([]) // false

isPrimitive(function() {}) // false

isPrimitive(new Date()) // false

isPrimitive(/a/) // false

```

### [just-filter-object](https://www.npmjs.com/package/just-filter-object)

[source](https://github.com/angus-c/just/tree/master/packages/object-filter)

[`🍦 Try it`](https://anguscroll.com/just/just-filter-object)

```shell

npm install just-filter-object

```

```shell

yarn add just-filter-object

```

Filter an object

```js

import filter from 'just-filter';

// returns a new object containing those original properties for which the predicate returns truthy

filter({a: 3, b: 5, c: 9}, (key, value) => value < 6); // {a: 3, b: 5}

filter({a1: 3, b1: 5, a2: 9}, (key, value) => key[0] == 'a'); // {a1: 3, a2: 9}

filter({a: 3, b: 5, c: null}, (key, value) => value); // {a: 3, b: 5}

```

### [just-map-object](https://www.npmjs.com/package/just-map-object)

[source](https://github.com/angus-c/just/tree/master/packages/object-map)

[`🍦 Try it`](https://anguscroll.com/just/just-map-object)

```shell

npm install just-map-object

```

```shell

yarn add just-map-object

```

Map an object, passing key and value to predicates

```js

import map from 'just-map-object';

// DEPRECATED: use just-map-values

map({a: 3, b: 5, c: 9}, (key, value) => value + 1); // {a: 4, b: 6, c: 10}

map({a: 3, b: 5, c: 9}, (key, value) => key); // {a: 'a', b: 'b', c: 'c'}

map({a: 3, b: 5, c: 9}, (key, value) => key + value); // {a: 'a3', b: 'b5', c: 'c9'}```

```

### [just-map-values](https://www.npmjs.com/package/just-map-values)

[source](https://github.com/angus-c/just/tree/master/packages/object-map-values)

[`🍦 Try it`](https://anguscroll.com/just/just-map-values)

```shell

npm install just-map-values

```

```shell

yarn add just-map-values

```

Map an object, predicate updates values, receives (value, key, object)

```js

import map from 'just-map-values';

// predicate updates values, receives (value, key, obj)

map({a: 3, b: 5, c: 9}, (value) => value + 1); // {a: 4, b: 6, c: 10}

map({a: 3, b: 5, c: 9}, (value, key) => value + key); // {a: 3a, b: 5b, c: 9c}

map({a: 3, b: 5, c: 9}, (value, key, obj) => obj.b); // {a: 5, b: 5, c: 5}

```

### [just-map-keys](https://www.npmjs.com/package/just-map-keys)

[source](https://github.com/angus-c/just/tree/master/packages/object-map-keys)

[`🍦 Try it`](https://anguscroll.com/just/just-map-keys)

```shell

npm install just-map-keys

```

```shell

yarn add just-map-keys

```

Map an object, predicate updates keys, receives (value, key, object)

```js

import map from 'just-map-keys';

// predicate updates keys, receives (value, key, object)

map({a: 'cow', b: 'sheep', c: 'pig'}, (value) => value);

  // {cow: 'cow', sheep: 'sheep', pig: 'pig'}

map([4, 5, 6], (value, key) => key + 1); // {1: 4, 2: 5, 3: 6}

map({a: 3, b: 5, c: 9}, (value, key) => key + value); // {a3: 3, b5: 5, c9: 9}

map({a: 3, b: 5, c: 9}, (value, key, obj) => obj.b + value + key);

  // {'8a': 3, '10b': 5, '14c': 9}

```

### [just-deep-map-values](https://www.npmjs.com/package/just-deep-map-values)

[source](https://github.com/angus-c/just/tree/master/packages/object-deep-map-values)

[`🍦 Try it`](https://anguscroll.com/just/just-deep-map-values)

```shell

npm install just-deep-map-values

```

```shell

yarn add just-deep-map-values

```

Returns an object with values at all depths mapped according to the provided function

```js

import deepMapValues from 'just-deep-map-values';

const squareFn = (number) => number * number;

deepMapValues({ a: 1, b: { c: 2, d: { e: 3 } } }, squareFn); // => { a: 1, b: { c: 4, d: { e: 9 } } }

```

### [just-reduce-object](https://www.npmjs.com/package/just-reduce-object)

[source](https://github.com/angus-c/just/tree/master/packages/object-reduce)

[`🍦 Try it`](https://anguscroll.com/just/just-reduce-object)

```shell

npm install just-reduce-object

```

```shell

yarn add just-reduce-object

```

Reduce an object

```js

import reduce from 'just-reduce-object';

// applies a function against an accumulator and each key-value pairs of the object

// to reduce it to a single value

reduce({a: 3, b: 5, c: 9}, (acc, key, value, index, keys) => {

  acc[value] = key;

  return acc;

}, {}); // {3: 'a', 5: 'b', 9: 'c'}

reduce({a: 3, b: 5, c: 9}, (acc, key, value, index, keys) => {

  acc += value;

  return acc;

}); // 17

```

### [just-safe-get](https://www.npmjs.com/package/just-safe-get)

[source](https://github.com/angus-c/just/tree/master/packages/object-safe-get)

[`🍦 Try it`](https://anguscroll.com/just/just-safe-get)

```shell

npm install just-safe-get

```

```shell

yarn add just-safe-get

```

Get value at property, don't throw if parent is undefined

```js

import get from 'just-safe-get';

const obj = {a: {aa: {aaa: 2}}, b: 4};

get(obj, 'a.aa.aaa'); // 2

get(obj, ['a', 'aa', 'aaa']); // 2

get(obj, 'b.bb.bbb'); // undefined

get(obj, ['b', 'bb', 'bbb']); // undefined

get(obj.a, 'aa.aaa'); // 2

get(obj.a, ['aa', 'aaa']); // 2

get(obj.b, 'bb.bbb'); // undefined

get(obj.b, ['bb', 'bbb']); // undefined

get(obj.b, 'bb.bbb', 5); // 5

get(obj.b, ['bb', 'bbb'], true); // true

get(null, 'a'); // undefined

get(undefined, ['a']); // undefined

get(null, 'a', 42); // 42

get(undefined, ['a'], 42); // 42

const obj = {a: {}};

const sym = Symbol();

obj.a[sym] = 4;

get(obj.a, sym); // 4

```

### [just-safe-set](https://www.npmjs.com/package/just-safe-set)

[source](https://github.com/angus-c/just/tree/master/packages/object-safe-set)

[`🍦 Try it`](https://anguscroll.com/just/just-safe-set)

```shell

npm install just-safe-set

```

```shell

yarn add just-safe-set

```

Set value at property, create intermediate properties if necessary

```js

import set from 'just-safe-set';

const obj1 = {};

set(obj1, 'a.aa.aaa', 4); // true

obj1; // {a: {aa: {aaa: 4}}}

const obj2 = {};

set(obj2, ['a', 'aa', 'aaa'], 4); // true

obj2; // {a: {aa: {aaa: 4}}}

const obj3 = {a: {aa: {aaa: 2}}};

set(obj3, 'a.aa.aaa', 3); // true

obj3; // {a: {aa: {aaa: 3}}}

const obj5 = {a: {}};

const sym = Symbol();

set(obj5.a, sym, 7); // true

obj5; // {a: {Symbol(): 7}}

```

### [just-typeof](https://www.npmjs.com/package/just-typeof)

[source](https://github.com/angus-c/just/tree/master/packages/object-typeof)

[`🍦 Try it`](https://anguscroll.com/just/just-typeof)

```shell

npm install just-typeof

```

```shell

yarn add just-typeof

```

Type inferer

```js

import typeOf from 'just-typeof';

typeOf({}); // 'object'

typeOf([]); // 'array'

typeOf(function() {}); // 'function'

typeOf(/a/); // 'regexp'

typeOf(new Date()); // 'date'

typeOf(null); // 'null'

typeOf(undefined); // 'undefined'

typeOf('a'); // 'string'

typeOf(1); // 'number'

typeOf(true); // 'boolean'

```

### [just-flip-object](https://www.npmjs.com/package/just-flip-object)

[source](https://github.com/angus-c/just/tree/master/packages/object-flip)

[`🍦 Try it`](https://anguscroll.com/just/just-flip-object)

```shell

npm install just-flip-object

```

```shell

yarn add just-flip-object

```

Flip the keys and values

```js

import flip from 'just-flip-object';

// flip the key and value

flip({a: 'x', b: 'y', c: 'z'}); // {x: 'a', y: 'b', z: 'c'}

flip({a: 1, b: 2, c: 3}); // {'1': 'a', '2': 'b', '3': 'c'}

flip({a: false, b: true}); // {false: 'a', true: 'b'}

```

### [just-has](https://www.npmjs.com/package/just-has)

[source](https://github.com/angus-c/just/tree/master/packages/object-has)

[`🍦 Try it`](https://anguscroll.com/just/just-has)

```shell

npm install just-has

```

```shell

yarn add just-has

```

Return a boolen indicating the existence of a deep property, don't throw if parent is undefined

```js

import has from 'just-has';

const obj = {a: {aa: {aaa: 2}}, b: 4};

has(obj, 'a.aa.aaa'); // true

has(obj, ['a', 'aa', 'aaa']); // true

has(obj, 'b.bb.bbb'); // false

has(obj, ['b', 'bb', 'bbb']); // false

has(obj.a, 'aa.aaa'); // true

has(obj.a, ['aa', 'aaa']); // true

has(obj.b, 'bb.bbb'); // false

has(obj.b, ['bb', 'bbb']); // false

has(null, 'a'); // false

has(undefined, ['a']); // false

const obj = {a: {}};

const sym = Symbol();

obj.a[sym] = 4;

has(obj.a, sym); // true

```

### Arrays

### [just-cartesian-product](https://www.npmjs.com/package/just-cartesian-product)

[source](https://github.com/angus-c/just/tree/master/packages/array-cartesian-product)

[`🍦 Try it`](https://anguscroll.com/just/just-cartesian-product)

```shell

npm install just-cartesian-product

```

```shell

yarn add just-cartesian-product

```

Takes an input of an array of arrays and returns their Cartesian product.

```js

import cartesianProduct from 'just-cartesian-product';

cartesianProduct([[1, 2], ['a', 'b']]); // [[1, 'a'], [1, 'b'], [2, 'a'], [2, 'b']]

cartesianProduct([[1, 2], ['a', 'b', 'c']]); // [[1, 'a'], [1, 'b'], [1, 'c'], [2, 'a'], [2, 'b'], [2, 'c']]

cartesianProduct([]); // []

cartesianProduct(); // throws

```

### [just-unique](https://www.npmjs.com/package/just-unique)

[source](https://github.com/angus-c/just/tree/master/packages/array-unique)

[`🍦 Try it`](https://anguscroll.com/just/just-unique)

```shell

npm install just-unique

```

```shell

yarn add just-unique

```

Dedupes an array

```js

import unique from 'just-unique';

unique([1, 2, 3, 2, 3, 4, 3, 2, 1, 3]); // [1, 2, 3, 4]

var a = {a: 3};

var b = {b: 4};

var c = {c: 5};

unique([a, a, b, c, b]); // [a, b, c]

unique([1, '1', 2, '2', 3, 2]); // [1, '1', 2, '2', 3]

// declaring sorted array for performance

unique([1, 1, '1', 2, 2, 5, '5', '5'], true); // [1, '1', 2, 5, '6']

// declaring strings array for performance

unique(['a', 'c', 'b', 'c', 'a'], false, true); // ['a', 'b', 'c']

```

### [just-flatten-it](https://www.npmjs.com/package/just-flatten-it)

[source](https://github.com/angus-c/just/tree/master/packages/array-flatten)

[`🍦 Try it`](https://anguscroll.com/just/just-flatten-it)

```shell

npm install just-flatten-it

```

```shell

yarn add just-flatten-it

```

Return a flattened array

```js

import flatten from 'just-flatten-it';

flatten([[1, [2, 3]], [[4, 5], 6, 7, [8, 9]]]);

// [1, 2, 3, 4, 5, 6, 7, 8, 9]

flatten([[1, [2, 3]], [[4, 5], 6, 7, [8, 9]]], 1);

// [1, [2, 3], [[4, 5], 6, 7, [8, 9]]]

```

### [just-index](https://www.npmjs.com/package/just-index)

[source](https://github.com/angus-c/just/tree/master/packages/array-index)

[`🍦 Try it`](https://anguscroll.com/just/just-index)

```shell

npm install just-index

```

```shell

yarn add just-index

```

Return an object from an array, keyed by the value at the given id

```js

import index from 'just-index';

index([{id: 'first', val: 1}, {id: 'second', val: 2}], 'id');

// {first: {id: 'first', val: 1}, second: {id: 'second', val: 2}}

index([{id: 'first', val: 1}, null], 'id'); // {first: {id: 'first', val: 1}}

index([], 'id'); // {}

index([], null); // undefined

index({}, 'id'); // undefined

```

### [just-insert](https://www.npmjs.com/package/just-insert)

[source](https://github.com/angus-c/just/tree/master/packages/array-insert)

[`🍦 Try it`](https://anguscroll.com/just/just-insert)

```shell

npm install just-insert

```

```shell

yarn add just-insert

```

Inserts a sub-array into an array starting at the given index. Returns a copy

```js

import insert from 'just-insert';

insert([1, 2, 5, 6], ['a', 'c', 'e'], 2); // [1, 2, 'a', 'c', 'e', 5, 6]

insert([1, 2, 5, 6], 'a', 2); // [1, 2, 'a', 5, 6]

insert([1, 2, 5, 6], ['a', 'c', 'e'], 0); // ['a', 'c', 'e', 1, 2, 5, 6]

insert([1, 2, 5, 6], ['a', 'c', 'e']); // ['a', 'c', 'e', 1, 2, 5, 6]

```

### [just-intersect](https://www.npmjs.com/package/just-intersect)

[source](https://github.com/angus-c/just/tree/master/packages/array-intersect)

[`🍦 Try it`](https://anguscroll.com/just/just-intersect)

```shell

npm install just-intersect

```

```shell

yarn add just-intersect

```

Return the intersect of two arrays

```js

import intersect from 'just-intersect';

intersect([1, 2, 5, 6], [2, 3, 5, 6]); // [2, 5, 6]

intersect([1, 2, 2, 4, 5], [3, 2, 2, 5, 7]); // [2, 5]  

```

### [just-compact](https://www.npmjs.com/package/just-compact)

[source](https://github.com/angus-c/just/tree/master/packages/array-compact)

[`🍦 Try it`](https://anguscroll.com/just/just-compact)

```shell

npm install just-compact

```

```shell

yarn add just-compact

```

Returns a copy of an array with falsey values removed

```js

import compact from 'just-compact';

compact([1, null, 2, undefined, null, NaN, 3, 4, false, 5]); // [1, 2, 3, 4, 5]

compact([1, 2, [], 4, {}]); // [1, 2, [], 4, {}]

compact([]); // []

compact({}); // throws

```

### [just-last](https://www.npmjs.com/package/just-last)

[source](https://github.com/angus-c/just/tree/master/packages/array-last)

[`🍦 Try it`](https://anguscroll.com/just/just-last)

```shell

npm install just-last

```

```shell

yarn add just-last

```

Return the last member of an array

```js

import last from 'just-last';

last([1, 2, 3, 4, 5]); // 5

last([{a: 1}, {b: 1}, {c: 1}]); // {c: 1}

last([true, false, [true, false]]); // [true, false]

last(); // undefined

last([]); // undefined

last(null); // undefined

last(undefined); // undefined

```

### [just-tail](https://www.npmjs.com/package/just-tail)

[source](https://github.com/angus-c/just/tree/master/packages/array-tail)

[`🍦 Try it`](https://anguscroll.com/just/just-tail)

```shell

npm install just-tail

```

```shell

yarn add just-tail

```

Return all but the first element of an array

```js

import tail from 'just-tail';

tail([1, 2, 3, 4, 5]); // [2, 3, 4, 5]

tail([{a: 1}, {b: 1}, {c: 1}]); // [{b: 1}, {c: 1}]

tail([true, false, [true, false]]); // [false, [true, false]]

tail([]); // []

tail(); // undefined

tail(null); // undefined

tail(undefined); // undefined

```

### [just-random](https://www.npmjs.com/package/just-random)

[source](https://github.com/angus-c/just/tree/master/packages/array-random)

[`🍦 Try it`](https://anguscroll.com/just/just-random)

```shell

npm install just-random

```

```shell

yarn add just-random

```

Return a randomly selected element in an array

```js

import random from 'just-random';

random([1, 2, 3]);

// one of [1, 2, 3], at random

```

### [just-shuffle](https://www.npmjs.com/package/just-shuffle)

[source](https://github.com/angus-c/just/tree/master/packages/array-shuffle)

[`🍦 Try it`](https://anguscroll.com/just/just-shuffle)

```shell

npm install just-shuffle

```

```shell

yarn add just-shuffle

```

Return the elements of an array in random order

```js

import shuffle from 'just-shuffle';

shuffle([1, 2, 3]); 

// array with original elements randomly sorted

shuffle([1, 2, 3], {shuffleAll: true}); 

// array with original elements randomly sorted and all in new postions

shuffle([]); // []

shuffle([1]); // [1]

shuffle(); // throws

shuffle(undefined); // throws

shuffle(null); // throws

shuffle({}); // throws

```

### [just-split](https://www.npmjs.com/package/just-split)

[source](https://github.com/angus-c/just/tree/master/packages/array-split)

[`🍦 Try it`](https://anguscroll.com/just/just-split)

```shell

npm install just-split

```

```shell

yarn add just-split

```

Splits array into groups of n items each

```js

import split from 'just-split';

split([]); // []

split([1, 2, 3, 4, 5]); // [[1, 2, 3, 4, 5]]

split([1, 2, 3, 4, 5, 6, 7, 8, 9], 3); // [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

split([1, 2, 3, 4, 5, 6, 7, 8, 9], '3'); // [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

split(['a', 'b', 'c', 'd', 'e'], 2); // [['a', 'b'], ['c', 'd'], ['e']]

split([1, 2, 3, 4, 5, 6, 7, 8], 3); // [[1, 2, 3], [4, 5, 6], [7, 8]]

```

### [just-split-at](https://www.npmjs.com/package/just-split-at)

[source](https://github.com/angus-c/just/tree/master/packages/array-split-at)

[`🍦 Try it`](https://anguscroll.com/just/just-split-at)

```shell

npm install just-split-at

```

```shell

yarn add just-split-at

```

Splits an array into two at a given position

```js

import splitAt from 'just-split-at';

splitAt([1, 2, 3, 4, 5], 2); // [[1, 2], [3, 4, 5]]

splitAt([{a: 1}, {b: 1}, {c: 1}], -1); // [[{a: 1}, {b: 1}], [{c: 1}]]

splitAt([], 2); // [[], []]

splitAt(null, 1); // throws

splitAt(undefined, 1); // throws

```

### [just-order-by](https://www.npmjs.com/package/just-order-by)

[source](https://github.com/angus-c/just/tree/master/packages/array-order-by)

[`🍦 Try it`](https://anguscroll.com/just/just-order-by)

```shell

npm install just-order-by

```

```shell

yarn add just-order-by

```

Produces a new array, sorted in given order

```js

import orderBy from 'just-order-by';

orderBy([10, 1, 5, 20, 15, 35, 30, 6, 8]); // [1, 5, 6, 8, 10, 15, 20, 30, 35]

orderBy(

  [

    { user: 'fabio', details: { city: 'Milan', age: 34 } },

    { user: 'max', details: { city: 'Munich', age: 29 } },

    { user: 'zacarias', details: { city: 'Sao Paulo', age: 44 } },

    { user: 'robert', details: { city: 'Manchester', age: 28 } },

    { user: 'max', details: { city: 'Zurich', age: 38 } },

  ],

  [

    {

      property(v) {

        return v.details.age;

      },

    },

  ]

);

/*

[

  {user: 'robert', age: 28},

  {user: 'max', age: 29},

  {user: 'fabio', age: 34},

  {user: 'klaus', age: 38},

  {user: 'zacarias', age: 44},

]

*/

orderBy(

  [

    {user: 'fabio', age: 34},

    {user: 'max', age: 29},

    {user: 'zacarias', age: 44},

    {user: 'robert', age: 28},

    {user: 'klaus', age: 38},

  ],

  [

    {

      property: 'user',

    },

  ]

);

/*

[

  {user: 'fabio', age: 34},

  {user: 'klaus', age: 38},

  {user: 'max', age: 29},

  {user: 'robert', age: 28},

  {user: 'zacarias', age: 44},

]

*/

orderBy(

  [

    { user: 'fabio', age: 34 },

    { user: 'max', age: 29 },

    { user: 'zacarias', age: 44 },

    { user: 'moris', age: 28 },

    { user: 'max', age: 38 },

  ],

  [

    {

      property: 'user',

      order: 'desc',

    },

    {

      property(v) {

        return v.age;

      },

    },

  ]

);

/*

[

  {

    user: 'zacarias',

    age: 44

  },

  {

    user: 'moris',

    age: 28

  },

  {

    user: 'max',

    age: 29

  },

  {

    user: 'max',

    age: 38

  },

  {

    user: 'fabio',

    age: 34

  }

]

*/

```

### [just-sort-by](https://www.npmjs.com/package/just-sort-by)

[source](https://github.com/angus-c/just/tree/master/packages/array-sort-by)

[`🍦 Try it`](https://anguscroll.com/just/just-sort-by)

```shell

npm install just-sort-by

```

```shell

yarn add just-sort-by

```

Produces a new array, sorted in ascending order

```js

import sortBy from 'just-sort-by';

sortBy([10, 1, 5, 20, 15, 35, 30, 6, 8]); // [1, 5, 6, 8, 10, 15, 20, 30, 35]

sortBy([

  {user: 'fabio', details: {city: "Milan", age: 34}},

  {user: 'max', details: {city: "Munich", age: 29}},

  {user: 'zacarias', details: {city: "Sao Paulo", age: 44}},

  {user: 'robert', details: {city: "Manchester", age: 28}},

  {user: 'klaus', details: {city: "Zurich", age: 38}},

], function(o) {

  return o.details.age;

});

/*

[

  {user: 'robert', age: 28},

  {user: 'max', age: 29},

  {user: 'fabio', age: 34},

  {user: 'klaus', age: 38},

  {user: 'zacarias', age: 44},

]

*/

sortBy([

  {user: 'fabio', age: 34},

  {user: 'max', age: 29},

  {user: 'zacarias', age: 44},

  {user: 'robert', age: 28},

  {user: 'klaus', age: 38},

], 'user');

/*

[

  {user: 'fabio', age: 34},

  {user: 'klaus', age: 38},

  {user: 'max', age: 29},

  {user: 'robert', age: 28},

  {user: 'zacarias', age: 44},

]

*/

```

### [just-partition](https://www.npmjs.com/package/just-partition)

[source](https://github.com/angus-c/just/tree/master/packages/array-partition)

[`🍦 Try it`](https://anguscroll.com/just/just-partition)

```shell

npm install just-partition

```

```shell

yarn add just-partition

```

Elements satisfying predicate added to first array, remainder added to second

```js

import partition from 'just-partition';

partition([1, 5, 2, 4, 3], n => n > 3); // [[5, 4],[1, 2, 3]]

partition(['a', 2, 3, '3'], x => typeof x == 'string'); // [['a', '3'],[2, 3]]

partition([1, 2, 3, 4], x => typeof x == 'number'); // [[1, 2, 3, 4],[]]

partition([1, 2, 3, 4], x => typeof x == 'string'); // [[], [1, 2, 3, 4]]

partition([], n => n > 3); // [[], []]

partition({a: 1, b: 2}, n => n > 1); // throws

partition(null, n => n > 1); // throws

partition(undefined, n => n > 1); // throws

```

### [just-permutations](https://www.npmjs.com/package/just-permutations)

[source](https://github.com/angus-c/just/tree/master/packages/array-permutations)

[`🍦 Try it`](https://anguscroll.com/just/just-permutations)

```shell

npm install just-permutations

```

```shell

yarn add just-permutations

```

Returns all permutations of the length N of the elements of the given Array

```js

import permutations from 'just-permutations';

permutations([1, 2, 3]); // [[1, 2, 3], [2, 1, 3], [2, 3, 1], [1, 3, 2], [3, 1, 2], [3, 2, 1]]

permutations([]); // []

permutations(); // throws

```

### [just-range](https://www.npmjs.com/package/just-range)

[source](https://github.com/angus-c/just/tree/master/packages/array-range)

[`🍦 Try it`](https://anguscroll.com/just/just-range)

```shell

npm install just-range

```

```shell

yarn add just-range

```

Generate a range array for numbers

```js

import range from 'just-range';

range(1, 5); // [1, 2, 3, 4]

range(5); // [0, 1, 2, 3, 4]

range(-5); // [0, -1, -2, -3, -4]

range(0, 20, 5) // [0, 5, 10, 15]

```

### [just-remove](https://www.npmjs.com/package/just-remove)

[source](https://github.com/angus-c/just/tree/master/packages/array-remove)

[`🍦 Try it`](https://anguscroll.com/just/just-remove)

```shell

npm install just-remove

```

```shell

yarn add just-remove

```

Removes one array from another

```js

import remove from 'just-remove';

remove([1, 2, 3, 4, 5, 6], [1, 3, 6]); // [2, 4, 5]

```

### [just-union](https://www.npmjs.com/package/just-union)

[source](https://github.com/angus-c/just/tree/master/packages/array-union)

[`🍦 Try it`](https://anguscroll.com/just/just-union)

```shell

npm install just-union

```

```shell

yarn add just-union

```

Returns the union of two arrays

```js

import union from 'just-union';

union([1, 2, 5, 6], [2, 3, 4, 6]); // [1, 2, 5, 6, 3, 4]

```

### [just-zip-it](https://www.npmjs.com/package/just-zip-it)

[source](https://github.com/angus-c/just/tree/master/packages/array-zip)

[`🍦 Try it`](https://anguscroll.com/just/just-zip-it)

```shell

npm install just-zip-it

```

```shell

yarn add just-zip-it

```

Returns an array of grouped elements, taking n-th element from every given array

```js

import zip from 'just-zip-it';

zip([1, 2, 3]); // [[1], [2], [3]]

zip([1, 2, 3], ['a', 'b', 'c']); // [[1, 'a'], [2, 'b'], [3, 'c']]

zip([1, 2], ['a', 'b'], [true, false]); //[[1, 'a', true], [2, 'b', false]]

zip(undefined, {}, false, 1, 'foo'); // []

zip([1, 2], ['a', 'b'], undefined, {}, false, 1, 'foo'); // [[1, 'a'], [2, 'b']]

zip([1, 2, 3], ['a', 'b'], [true]); // [[1, 'a', true], [2, 'b', undefined], [3, undefined, undefined]]

```

### [just-group-by](https://www.npmjs.com/package/just-group-by)

[source](https://github.com/angus-c/just/tree/master/packages/array-group-by)

[`🍦 Try it`](https://anguscroll.com/just/just-group-by)

```shell

npm install just-group-by

```

```shell

yarn add just-group-by

```

Return a grouped object from array

```js

import groupBy from 'just-group-by';

groupBy([6.1, 4.2, 6.3], Math.floor); // { '4': [4.2], '6': [6.1, 6.3] }

groupBy([1,2,3,4,5,6,7,8], function(i) { return i % 2}); // { '0': [2, 4, 6, 8], '1': [1, 3, 5, 7] }

```

### Statistics

### [just-mean](https://www.npmjs.com/package/just-mean)

[source](https://github.com/angus-c/just/tree/master/packages/array-mean)

[`🍦 Try it`](https://anguscroll.com/just/just-mean)

```shell

npm install just-mean

```

```shell

yarn add just-mean

```

The mean (average) value in an array

```js

import mean from 'just-mean';

mean([1, 2, 3, 2, 4, 1]); // 2.1666666667

mean(3, 2, 1); // 2

mean([4]); // 4

mean(['3', 2]); // throws

mean(); // throws

```

### [just-median](https://www.npmjs.com/package/just-median)

[source](https://github.com/angus-c/just/tree/master/packages/array-median)

[`🍦 Try it`](https://anguscroll.com/just/just-median)

```shell

npm install just-median

```

```shell

yarn add just-median

```

Return the median value of an array of numbers

```js

import median from 'just-median';

median([1, 2, 3, 4, 5]); // 3

median([3, -1, 2]); // 2

median([9, 14, 14, 200, 15]); // 14

median(1, 2, 4, 3); // 2.5

median(['3', 2, 1]); // throws

median(); // throws

```

### [just-mode](https://www.npmjs.com/package/just-mode)

[source](https://github.com/angus-c/just/tree/master/packages/array-mode)

[`🍦 Try it`](https://anguscroll.com/just/just-mode)

```shell

npm install just-mode

```

```shell

yarn add just-mode

```

Return the most frequently occuring number(s)

```js

import mode from 'just-mode';

mode([1, 2, 3, 2]); // 2

mode(4, 4, 1, 4); // 4

mode(100, 100, 101, 101); // [100, 101]

mode(4, 3, 2, 1); // [1, 2, 3, 4]

mode(['1', 2, 2, 1, 2]); // throws

mode(null); // throws

```

### [just-percentile](https://www.npmjs.com/package/just-percentile)

[source](https://github.com/angus-c/just/tree/master/packages/array-percentile)

[`🍦 Try it`](https://anguscroll.com/just/just-percentile)

```shell

npm install just-percentile

```

```shell

yarn add just-percentile

```

Return the value at the given percentile (using linear interpolation)

```js

import percentile from 'just-percentile';

percentile([1, 2, 3], 0); // 1

percentile([1, 2, 3], 0.5); // 2

percentile([1, 2, 3], 1); // 3

// See https://en.wikipedia.org/wiki/Percentile (linear interpolation method)

percentile([15, 20, 35, 40, 50], 0.05); // 15

percentile([15, 20, 35, 40, 50], 0.3); // 20

percentile([15, 20, 35, 40, 50], 0.4); // 27.5

percentile([15, 20, 35, 40, 50], 0.95); // 50

percentile(1, 2, 3, 50); // throws

percentile(['1', 2, 3], 50); // throws

percentile([], 50); // throws

```

### [just-variance](https://www.npmjs.com/package/just-variance)

[source](https://github.com/angus-c/just/tree/master/packages/array-variance)

[`🍦 Try it`](https://anguscroll.com/just/just-variance)

```shell

npm install just-variance

```

```shell

yarn add just-variance

```

Return the standard deviation of an array or numeric argument list

```js

import variance from 'just-variance';

variance([1, 2, 3, 2, 4, 1]); // 1.3666666667

variance(3, 2, 1); // 1

variance([100, 100, 100.1, 100]); // 0.0025

variance(1, 2, 3, 4, 5, -6); // 15.5

variance([4]); // throws

variance(['3', 2]); // throws

variance(NaN, NaN); // throws

variance(); // throws

```

### [just-standard-deviation](https://www.npmjs.com/package/just-standard-deviation)

[source](https://github.com/angus-c/just/tree/master/packages/array-standard-deviation)

[`🍦 Try it`](https://anguscroll.com/just/just-standard-deviation)

```shell

npm install just-standard-deviation

```

```shell

yarn add just-standard-deviation

```

Return the standard deviation of an array or numeric argument list

```js

import standardDeviation from "just-standard-deviation";

standardDeviation([1, 2, 3, 2, 4, 1]); // 1.16904519

standardDeviation(3, 2, 1); // 1

standardDeviation([100, 100, 100.1, 100]); // 0.05

standardDeviation(1, 2, 3, 4, 5, -6); // 3.9370039

standardDeviation([4]); // throws

standardDeviation(["3", 2]); // throws

standardDeviation(NaN, NaN); // throws

standardDeviation(); // throws

```

### [just-skewness](https://www.npmjs.com/package/just-skewness)

[source](https://github.com/angus-c/just/tree/master/packages/array-skewness)

[`🍦 Try it`](https://anguscroll.com/just/just-skewness)

```shell

npm install just-skewness

```

```shell

yarn add just-skewness

```

Return the skewness of an array or numeric argument list using Pearson's second skewness coefficient

```js

import skewness from "just-skewness";

// Using Pearson's second skewness coefficient

skewness(3, 2, 1); // 0

skewness([1, 2, 3, 2, 4, 1]); // 0.4276994613841504

skewness(1, 2, 3, 4, 5, -6); // -0.762000762001143

skewness([1, 2, 3, 4, 9]); // 0.7705935588815224

skewness([4]); // throws

skewness(["3", 2]); // throws

skewness(NaN, NaN); // throws

skewness(); // throws

```

### Strings

### [just-template](https://www.npmjs.com/package/just-template)

[source](https://github.com/angus-c/just/tree/master/packages/string-template)

[`🍦 Try it`](https://anguscroll.com/just/just-template)

```shell

npm install just-template

```

```shell

yarn add just-template

```

Interpolate a string with variables

```js

import template from 'just-template';

var data = {

  a: {

    aa: {

      aaa: 'apple',

      bbb: 'pear'

    },

    bb: 'orange'

  },

  b: 'plum'

};

template('2 {{a.aa.aaa}}s, a {{a.aa.bbb}}, 3 {{a.bb}}s and a {{b}}. Yes 1 {{a.aa.bbb}}.', data);

// '2 apples, a pear, 3 oranges and a plum. Yes 1 pear.'

```

### [just-truncate](https://www.npmjs.com/package/just-truncate)

[source](https://github.com/angus-c/just/tree/master/packages/string-truncate)

[`🍦 Try it`](https://anguscroll.com/just/just-truncate)

```shell

npm install just-truncate

```

```shell

yarn add just-truncate

```

Truncate a string with a custom suffix

```js

  truncate('when shall we three meet again', 9); // 'when s...'

  truncate('when shall we three meet again', 10, ' (etc)'); // 'when (etc)'

  truncate('when shall we', 15,); // 'when shall we'

  truncate('when shall we', 15, '(more)'); // 'when shall we'

  truncate('when shall we', 10, ' (etc etc etc)'); // ' (etc etc etc)'

```

### [just-prune](https://www.npmjs.com/package/just-prune)

[source](https://github.com/angus-c/just/tree/master/packages/string-prune)

[`🍦 Try it`](https://anguscroll.com/just/just-prune)

```shell

npm install just-prune

```

```shell

yarn add just-prune

```

Prune a string with whole words and a custom suffix

```js

  prune('when shall we three meet again', 7); // 'when...'

  prune('when shall we three meet again', 7, ' (more)'; // 'when (more)'

  prune('when shall we', 15,); // 'when shall we'

  prune('when shall we', 15, ' (etc)'); // 'when shall we'

  prune('when shall we', 7, ' (more)'); // ' (more)'

```

### [just-squash](https://www.npmjs.com/package/just-squash)

[source](https://github.com/angus-c/just/tree/master/packages/string-squash)

[`🍦 Try it`](https://anguscroll.com/just/just-squash)

```shell

npm install just-squash

```

```shell

yarn add just-squash

```

Remove all spaces from a string, optionally remove escape sequences too

```js

  squash('the cat sat on the mat'); // 'thecatsatonthemat'

  squash(' the cat sat on the mat '); // 'thecatsatonthemat'

  squash('\tthe cat\n sat \fon \vthe \rmat '); // '\tthecat\nsat\fon\vthe\rmat'

  squash('\tthe cat\n sat \fon \vthe \rmat ', true); // 'thecatsatonthemat'

  squash(`the cat

sat on the mat`, true); // thecatsatonthemat

```

### [just-left-pad](https://www.npmjs.com/package/just-left-pad)

[source](https://github.com/angus-c/just/tree/master/packages/string-left-pad)

[`🍦 Try it`](https://anguscroll.com/just/just-left-pad)

```shell

npm install just-left-pad

```

```shell

yarn add just-left-pad

```

Add characters to the left of a string such that its total length is n

```js

import leftPad from 'just-left-pad';

leftPad('hello', 9); // '    hello'

leftPad('hello', 3); // 'hello'

leftPad('hello', 9, '.'); // '....hello'

leftPad('hello', 9, '..'); // '....hello'

leftPad('hello', 10, 'ab'); // 'bababhello'

leftPad('hello', 9, '\uD83D\uDC04'); // '🐄🐄🐄🐄hello'

leftPad('hello', 10, '\uD83D\uDC11\uD83D\uDC04'), // '🐄🐑🐄🐑🐄hello'

leftPad('hello', 7, '🐄'), // '🐄🐄hello'

leftPad(null, 7); // throws

leftPad([], 4, '*'); // throws

leftPad('hello', 4, true); // throws

leftPad('hello', -4, true); // throws  

leftPad('hello', 2.3, true); // throws    

```

### [just-right-pad](https://www.npmjs.com/package/just-right-pad)

[source](https://github.com/angus-c/just/tree/master/packages/string-right-pad)

[`🍦 Try it`](https://anguscroll.com/just/just-right-pad)

```shell

npm install just-right-pad

```

```shell

yarn add just-right-pad

```

Add characters to the right of a string such that its total length is n

```js

import rightPad from 'just-right-pad';

rightPad('hello', 9); // 'hello    '

rightPad('hello', 3); // 'hello'

rightPad('hello', 9, '.'); // 'hello....'

rightPad('hello', 9, '..'); // 'hello....'

rightPad('hello', 10, 'ab'); // 'helloababa'

rightPad('hello', 9, '\uD83D\uDC04'); // 'hello🐄🐄🐄🐄'

rightPad('hello', 10, '\uD83D\uDC11\uD83D\uDC04'), // 'hello🐑🐄🐑🐄🐑'

rightPad('hello', 7, '🐄'), // 'hello🐄🐄'

rightPad(null, 7); // throws

rightPad([], 4, '*'); // throws

rightPad('hello', 4, true); // throws

rightPad('hello', -4, true); // throws  

rightPad('hello', 2.3, true); // throws    

```

### [just-camel-case](https://www.npmjs.com/package/just-camel-case)

[source](https://github.com/angus-c/just/tree/master/packages/string-camel-case)

[`🍦 Try it`](https://anguscroll.com/just/just-camel-case)

```shell

npm install just-camel-case

```

```shell

yarn add just-camel-case

```

Convert a string to camel case

```js

  import camelCase from 'just-camel-case';

  camelCase('the quick brown fox'); // 'theQuickBrownFox'

  camelCase('the_quick_brown_fox'); // 'theQuickBrownFox'

  camelCase('the-quick-brown-fox'); // 'theQuickBrownFox'

  camelCase('theQuickBrownFox'); // 'theQuickBrownFox'

  camelCase('thequickbrownfox'); // 'thequickbrownfox'

  camelCase('the - quick * brown# fox'); // 'theQuickBrownFox'

  camelCase('behold theQuickBrownFox'); // 'beholdTheQuickBrownFox'

  camelCase('Behold theQuickBrownFox'); // 'beholdTheQuickBrownFox'

  // all caps words are camel-cased

  camelCase('The quick brown FOX'), 'theQuickBrownFox');

  // all caps substrings >= 4 chars are camel-cased

  camelCase('theQUickBrownFox'); // 'theQUickBrownFox'

  camelCase('theQUIckBrownFox'); // 'theQUIckBrownFox'

  camelCase('theQUICKBrownFox'); // 'theQuickBrownFox'

```

### [just-kebab-case](https://www.npmjs.com/package/just-kebab-case)

[source](https://github.com/angus-c/just/tree/master/packages/string-kebab-case)

[`🍦 Try it`](https://anguscroll.com/just/just-kebab-case)

```shell

npm install just-kebab-case

```

```shell

yarn add just-kebab-case

```

Convert a string to kebab case

```js

  import kebabCase from 'just-kebab-case';

  kebabCase('the quick brown fox'); // 'the-quick-brown-fox'

  kebabCase('the-quick-brown-fox'); // 'the-quick-brown-fox'

  kebabCase('the_quick_brown_fox'); // 'the-quick-brown-fox'

  kebabCase('theQuickBrownFox'); // 'the-quick-brown-fox'

  kebabCase('theQuickBrown Fox'); // 'the-quick-brown-fox'

  kebabCase('thequickbrownfox'); // 'thequickbrownfox'

  kebabCase('the - quick * brown# fox'); // 'the-quick-brown-fox'

  kebabCase('theQUICKBrownFox'); // 'the-q-u-i-c-k-brown-fox'

```

### [just-snake-case](https://www.npmjs.com/package/just-snake-case)

[source](https://github.com/angus-c/just/tree/master/packages/string-snake-case)

[`🍦 Try it`](https://anguscroll.com/just/just-snake-case)

```shell

npm install just-snake-case

```

```shell

yarn add just-snake-case

```

Convert a string to snake case

```js

  import snakeCase from 'just-snake-case';

  snakeCase('the quick brown fox'); // 'the_quick_brown_fox'

  snakeCase('the-quick-brown-fox'); // 'the_quick_brown_fox'

  snakeCase('the_quick_brown_fox'); // 'the_quick_brown_fox'

  snakeCase('theQuickBrownFox'); // 'the_quick_brown_fox'

  snakeCase('thequickbrownfox'); // 'thequickbrownfox'

  snakeCase('the - quick * brown# fox'); // 'the_quick_brown_fox'

  snakeCase('theQUICKBrownFox'); // 'the_q_u_i_c_k_brown_fox'

```

### [just-pascal-case](https://www.npmjs.com/package/just-pascal-case)

[source](https://github.com/angus-c/just/tree/master/packages/string-pascal-case)

[`🍦 Try it`](https://anguscroll.com/just/just-pascal-case)

```shell

npm install just-pascal-case

```

```shell

yarn add just-pascal-case

```

Convert a string to pascal case

```js

  import pascalCase from 'just-pascal-case';

  pascalCase('the quick brown fox'); // 'TheQuickBrownFox'

  pascalCase('the_quick_brown_fox'); // 'TheQuickBrownFox'

  pascalCase('the-quick-brown-fox'); // 'TheQuickBrownFox'

  pascalCase('theQuickBrownFox'); // 'TheQuickBrownFox'

  pascalCase('thequickbrownfox'); // 'Thequickbrownfox'

  pascalCase('the - quick * brown# fox'); // 'TheQuickBrownFox'

  pascalCase('theQUICKBrownFox'); // 'TheQUICKBrownFox'

```

### [just-capitalize](https://www.npmjs.com/package/just-capitalize)

[source](https://github.com/angus-c/just/tree/master/packages/string-capitalize)

[`🍦 Try it`](https://anguscroll.com/just/just-capitalize)

```shell

npm install just-capitalize

```

```shell

yarn add just-capitalize

```

Capitalize the first character of a string

```js

  import capitalize from 'just-capitalize';

/*

  capitalize('capitals'); // 'Capitals'

  capitalize('Capitals'); // 'Capitals'

  capitalize('many words'); // 'Many words'

  capitalize('!exclaim'); // '!exclaim'

*/

```

### [just-replace-all](https://www.npmjs.com/package/just-replace-all)

[source](https://github.com/angus-c/just/tree/master/packages/string-replace-all)

[`🍦 Try it`](https://anguscroll.com/just/just-replace-all)

```shell

npm install just-replace-all

```

```shell

yarn add just-replace-all

```

Replace all occurrences of a string within a string with another string

```js

  import replaceAll from 'just-replace-all';

/*

  replaceAll('hello, world', 'l', 'q'); // 'heqqo, worqd'

  replaceAll('hello, world', 'l', 'qq'); // 'heqqqqo, worqqd'

  replaceAll('hello, world', 'll', 'q'); // 'heqo, world'

  replaceAll('hello, world', '', 'q'); // 'hello, world'

  replaceAll('hello, world', 'l', ''); // 'heo, word'

  replaceAll('hello, world', null, 'q'); // 'hello, world'

  replaceAll('hello, world', 'l'); // throw

  replaceAll('hello, world'); // throw

  replaceAll(); // throw

  replaceAll(null, 'l', 'q'); // throw

  replaceAll('hello, world', null, 'q'); // throw

  replaceAll('hello, world', 'l', null); // throw

*/

```

### Numbers

### [just-clamp](https://www.npmjs.com/package/just-clamp)

[source](https://github.com/angus-c/just/tree/master/packages/number-clamp)

[`🍦 Try it`](https://anguscroll.com/just/just-clamp)

```shell

npm install just-clamp

```

```shell

yarn add just-clamp

```

Restrict a number within a range

```js

import clamp from 'just-clamp';

var n = 5;

clamp(1, n, 12); // 5

clamp(3, n, 1); // 3

clamp(8, n, 9); // 8

clamp(0, n, 0); // 0

var n = -5;

clamp(1, n, 12); // 1

clamp(-7, n, -8); // -7

clamp(NaN, n, 8); // NaN

clamp(3, n, NaN); // NaN  

clamp(3, NaN, 8); // NaN    

clamp(undefined, n, 8); // throws

clamp(3, n, 'h'); // throws  

clamp(3, false, 8); // throws 

```

### [just-is-prime](https://www.npmjs.com/package/just-is-prime)

[source](https://github.com/angus-c/just/tree/master/packages/number-is-prime)

[`🍦 Try it`](https://anguscroll.com/just/just-is-prime)

```shell

npm install just-is-prime

```

```shell

yarn add just-is-prime

```

Check if number is prime

```js

  import isPrime from 'just-is-prime;

/*

  isPrime(1); // false

  isPrime(2); // true

  isPrime(17); // true

  isPrime(10); // false

  isPrime(); // throws

  isPrime(null); // throws

  isPrime("js"); // throws

  isPrime({}); // throws

  isPrime(function() {}); // throws

  isPrime([]); // throws

*/

```

### [just-modulo](https://www.npmjs.com/package/just-modulo)

[source](https://github.com/angus-c/just/tree/master/packages/number-modulo)

[`🍦 Try it`](https://anguscroll.com/just/just-modulo)

```shell

npm install just-modulo

```

```shell

yarn add just-modulo

```

Modulo of a number and a divisor

```js

import modulo from 'just-modulo';

modulo(7, 5); // 2

modulo(17, 23); // 17

modulo(16.2, 3.8); // 1

modulo(5.8, 3.4); //2.4

modulo(4, 0); // 4

modulo(-7, 5); // 3

modulo(-2, 15); // 13

modulo(-5.8, 3.4); // 1

modulo(12, -1); // NaN

modulo(-3, -8); // NaN

modulo(12, 'apple'); // NaN

modulo('bee', 9); // NaN

modulo(null, undefined); // NaN

```

### [just-random-integer](https://www.npmjs.com/package/just-random-integer)

[source](https://github.com/angus-c/just/tree/master/packages/number-random-integer)

[`🍦 Try it`](https://anguscroll.com/just/just-random-integer)

```shell

npm install just-random-integer

```

```shell

yarn add just-random-integer

```

Produces a random integer within a given range

```js

import random from 'just-random-integer';

random();

// Returns either 0 or 1

random(5);

// Returns a random integer between 0 and 5 (inclusively)

random(3, 10);

// Returns a random integer between 3 and 10 (inclusively)

random(-5.8, 10.4);

// Returns a random integer between -5 and 10 (inclusively)

```

### Functions

### [just-compose](https://www.npmjs.com/package/just-compose)

[source](https://github.com/angus-c/just/tree/master/packages/function-compose)

[`🍦 Try it`](https://anguscroll.com/just/just-compose)

```shell

npm install just-compose

```

```shell

yarn add just-compose

```

Return a function composed of 2 or more functions

```js

import compose from 'just-compose';

const sqRootBiggest = compose(Math.max, Math.sqrt, Math.trunc);

sqRootBiggest(10, 5); // 3

sqRootBiggest(7, 0, 16); // 4

```

### [just-curry-it](https://www.npmjs.com/package/just-curry-it)

[source](https://github.com/angus-c/just/tree/master/packages/function-curry)

[`🍦 Try it`](https://anguscroll.com/just/just-curry-it)

```shell

npm install just-curry-it

```

```shell

yarn add just-curry-it

```

Return a curried function

```js

import curry from 'just-curry-it';

function add(a, b, c) {

  return a + b + c;

}

curry(add)(1)(2)(3); // 6

curry(add)(1)(2)(2); // 5

curry(add)(2)(4, 3); // 9

function add(...args) {

  return args.reduce((sum, n) => sum + n, 0)

}

var curryAdd4 = curry(add, 4)

curryAdd4(1)(2, 3)(4); // 10

function converter(ratio, input) {

  return (input*ratio).toFixed(1);

}

const curriedConverter = curry(converter)

const milesToKm = curriedConverter(1.62);

milesToKm(35); // 56.7

milesToKm(10); // 16.2

```

### [just-demethodize](https://www.npmjs.com/package/just-demethodize)

[source](https://github.com/angus-c/just/tree/master/packages/function-demethodize)

[`🍦 Try it`](https://anguscroll.com/just/just-demethodize)

```shell

npm install just-demethodize

```

```shell

yarn add just-demethodize

```

Turn a method into a standalone function; the first arg becomes `this`

```js

import demethodize from 'just-demethodize';

const trimFn = demethodize(''.trim);

['hello ', ' goodbye', 'hello again'].map(trimFn); // ['hello', 'goodbye', 'hello again']

```

### [just-flip](https://www.npmjs.com/package/just-flip)

[source](https://github.com/angus-c/just/tree/master/packages/function-flip)

[`🍦 Try it`](https://anguscroll.com/just/just-flip)

```shell

npm install just-flip

```

```shell

yarn add just-flip

```

Flip first two arguments of a function

```js

import flip from 'just-flip';

flip(console.log)(1, 2, 3) // 2, 1, 3

import map from 'just-map-object';

import partial from 'just-partial';

const numbers = {x: 5, y: 10};

const flippedMap = flip(map);

const double = partial(flippedMap, (undefined, number) => number * 2);

double(numbers) // {x: 10, y: 20];

```

### [just-partial-it](https://www.npmjs.com/package/just-partial-it)

[source](https://github.com/angus-c/just/tree/master/packages/function-partial)

[`🍦 Try it`](https://anguscroll.com/just/just-partial-it)

```shell

npm install just-partial-it

```

```shell

yarn add just-partial-it

```

Return a partial function

```js

import partial from 'just-partial-it';

const cubedRoot = partial(Math.pow, _, 1/3);

cubedRoot(64); // 4

const getRoot = partial(Math.pow, 64);

getRoot(1/2); // 8

```

### [just-pipe](https://www.npmjs.com/package/just-pipe)

[source](https://github.com/angus-c/just/tree/master/packages/function-pipe)

[`🍦 Try it`](https://anguscroll.com/just/just-pipe)

```shell

npm install just-pipe

```

```shell

yarn add just-pipe

```

Pass a value through a pipeline of functions

```js

import pipe from 'just-pipe

pipe(3, a => a+1, b => b*2) // 8

pipe('John Smith', a => a.split(' '), b => b.reverse(), c => c[0]) // 'Smith'

```

### [just-debounce-it](https://www.npmjs.com/package/just-debounce-it)

[source](https://github.com/angus-c/just/tree/master/packages/function-debounce)

[`🍦 Try it`](https://anguscroll.com/just/just-debounce-it)

```shell

npm install just-debounce-it

```

```shell

yarn add just-debounce-it

```

Return a debounced function

```js

import debounce from "just-debounce-it";

const fn1 = debounce(() => console.log("Hello"), 500);

fn1();

fn1();

fn1();

// 500ms later logs 'hello' once

const fn2 = debounce(() => console.log("Hello"), 500, true);

fn2(); // logs hello immediately

fn2();

fn2();

// 500ms later logs 'hello' once

const fn3 = debounce(() => console.log("Hello"), 500);

fn3();

fn3();

fn3();

fn3.cancel();

// function cancelled before 'hello' is logged

const fn4 = debounce(() => console.log("Hello"), 500);

fn4();

fn4();

fn4();

fn4.flush();

// immediately invoke the debounced function

```

### [just-memoize](https://www.npmjs.com/package/just-memoize)

[source](https://github.com/angus-c/just/tree/master/packages/function-memoize)

[`🍦 Try it`](https://anguscroll.com/just/just-memoize)

```shell

npm install just-memoize

```

```shell

yarn add just-memoize

```

An implementation of the memoize technique

```js

import memoize from 'just-memoize';

const sumByOne = memoize(function(value) {

  return value + 1;

});

sumByOne(10); // Returns value returned by the function

sumByOne(10); // Cache hit!

sumByOne(20); // Returns value returned by the function

sumByOne(20); // Cache hit!

// Custom cache key (key defaults to JSON stringified arguments)

var sum = memoize(function(a, b) {

  return a + b;

}, function(a, b) {

  return `${a}-${b}`;

});

sum(10, 10); // Returns value returned by the function

sum(10, 20); // Returns value returned by the function

sum(10, 20); // Cache hit!

```

### [just-memoize-last](https://www.npmjs.com/package/just-memoize-last)

[source](https://github.com/angus-c/just/tree/master/packages/function-memoize-last)

[`🍦 Try it`](https://anguscroll.com/just/just-memoize-last)

```shell

npm install just-memoize-last

```

```shell

yarn add just-memoize-last

```

A memoize implementation that only caches the most recent evaluation

```js

const memoizeLast = require('just-memoize-last')

const compare = require('just-compare')

const maxValue = memoizeLast(function(arr) {

  return Math.max(...arr)

}, function(a, b) {

  return compare(a, b)

});

maxValue([1,2,3]) // 3

maxValue([1,2,3]) // cache hit!

maxValue([1,3,4]) // 4

maxValue([1,2,3]) // 3

```

### [just-random](https://www.npmjs.com/package/just-random)

[source](https://github.com/angus-c/just/tree/master/packages/array-random)

[`🍦 Try it`](https://anguscroll.com/just/just-random)

```shell

npm install just-random

```

```shell

yarn add just-random

```

Return a randomly selected element in an array

```js

import random from 'just-random';

random([1, 2, 3]);

// one of [1, 2, 3], at random

```

### [just-throttle](https://www.npmjs.com/package/just-throttle)

[source](https://github.com/angus-c/just/tree/master/packages/function-throttle)

[`🍦 Try it`](https://anguscroll.com/just/just-throttle)

```shell

npm install just-throttle

```

```shell

yarn add just-throttle

```

Return a throttled function

```js

import throttle from 'just-throttle';

// no matter how many times the function is called, only invoke once within the given interval

// options: 

// `leading`: invoke  before interval

// `trailing`: invoke afer interval

const fn1 = throttle(() => console.log('hello'), 500, {leading: true});

setInterval(fn1, 400);

// logs 'hello' immediately and then every 500ms

const fn2 = throttle(() => console.log('hello'), 500, {trailing: true});

setInterval(fn2, 400);

// logs 'hello' after 500ms and then every 500ms

const fn3 = throttle(() => console.log('hello'), 500, {leading: true, trailing: true});

// forces trailing to false

const fn4 = throttle(() => console.log('hello'), 500, { leading: false });

fn4();

fn4();

fn4();

fn4.cancel();

// function cancelled before 'hello' is logged

const fn5 = throttle(() => console.log("Hello"), 500);

fn5();

fn5();

fn5();

fn5.flush();

// immediately invoke the throttled function

```

### [just-once](https://www.npmjs.com/package/just-once)

[source](https://github.com/angus-c/just/tree/master/packages/function-once)

[`🍦 Try it`](https://anguscroll.com/just/just-once)

```shell

npm install just-once

```

```shell

yarn add just-once

```

Create a function that can only be invoked once

```js

import once from 'just-once';

const fn = once(() => console.log('hello'));

fn();

// logs 'hello'

fn();

// does nothing

```

## Testing

Run all tests as a single test suite with

`npm run test`

Cross browser tests (via saucelabs) are in the [`sauce` branch](https://github.com/angus-c/just/tree/sauce)

## Contribute!

https://github.com/angus-c/just/blob/master/CONTRIBUTING.md