feat: shuffle function

CHANGELOG

@@ -1,3 +1,6 @@
+# 1.5.0
+- feat: shuffle
+
 # 1.4.0
 - feat: isObject
 

README.md

@@ -18,3 +18,4 @@ Currently supported utils:
 - `omitBy` - provides new object that omits only specific fields of source object depending on predicate function filter
 - `pick` - provides new object that picks only specific fields of source object
 - `pickBy` - provides new object that picks only specific fields of source object depending on predicate function filter
+- `shuffle` - performs pseudo random shuffle on clone of the array

index.d.ts

@@ -13,3 +13,4 @@ export function omit(obj: Object, keys: Array<string>): Object
 export function omitBy(obj: Object, predicate: (val: any, key: string) => boolean): Object
 export function pick(obj: Object, keys: Array<string>): Object
 export function pickBy(obj: Object, predicate: (val: any, key: string) => boolean): Object
+export function shuffle<T>(array: Array<T>): Array<T>

index.js

@@ -15,6 +15,7 @@ const omit = require('./src/omit')
 const omitBy = require('./src/omitBy')
 const pick = require('./src/pick')
 const pickBy = require('./src/pickBy')
+const shuffle = require('./src/shuffle')
 
 module.exports = {
  camelize,
@@ -31,5 +32,6 @@ module.exports = {
  omit,
  omitBy,
  pick,
- pickBy
+ pickBy,
+ shuffle
 }

package.json

@@ -1,6 +1,6 @@
 {
  "name": "@bitfinex/lib-js-util-base",
- "version": "1.4.0",
+ "version": "1.5.0",
  "description": "general utils",
  "main": "index.js",
  "scripts": {

src/shuffle.js

@@ -0,0 +1,22 @@
+'use strict'
+
+/**
+ * Performs pseudo random shuffles on clone of the array
+ *
+ * @param {Array<any>} array
+ * @returns {Array<any>}
+ */
+const shuffle = (array) => {
+ const clone = [...array]
+ const length = clone.length
+ for (let i = 0; i < length; i++) {
+ const mov = Math.floor(Math.random() * length)
+ const tmp = clone[mov]
+ clone[mov] = clone[i]
+ clone[i] = tmp
+ }
+
+ return clone
+}
+
+module.exports = shuffle

test/shuffle.js

@@ -0,0 +1,18 @@
+'use strict'
+
+/* eslint-env mocha */
+
+const assert = require('assert')
+const { shuffle } = require('../index')
+
+describe('shuffle', () => {
+ const array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+
+ it('should return a new array', () => {
+ assert.ok(shuffle(array).some((x, i) => array[i] !== x))
+ })
+
+ it('should contain the same elements after a collection is shuffled', () => {
+ assert.deepStrictEqual(shuffle(array).sort((a, b) => a - b), array)
+ })
+})