Shuffle arrays in place

ES-6 module with functions for shuffling arrays (shuffle, shuffleInplace) implemented using the Durstenfeld improvement to the Fisher-Yates algorithm (popularized by Knuth). Uses Math.random out-of-the-box, but allows user to inject any (pseudo) random number generator that have the same contract as Math.random. By injecting a seedable random numbergenerator the user can get seeded random shuffling that generates identical results for the same seed.

Verified to be reasonably evenly distributed by included tests.

Usage

Out-of-the-box shuffle in-place (uses Math.random)

import { shuffleInplace } from shuffle-es6

var list = [...Array(42).keys()]
shuffleInplace(list)

With another (pseudo) random number generator

import { shuffleInplace } from shuffle-es6

var list = [...Array(42).keys()]
shuffleInplace(list, Math.random)

If you want a copy and not inplace, then you can use shuffle as it wraps shuffleInplace makes a copy using Array.slice() before shuffling.

import { shuffle } from shuffle-es6

const inputList = [1,2,3,4,5,6]
var shuffledCopy = shuffle(inputList)

Install

npm install --save shuffle-es6