The Fisher-Yates (aka Knuth) shuffle for Browser and Node.js
- Mike Bostock's Fisher–Yates Shuffle Visualization
- How to randomize/shuffle a JavaScript array
- Fisher-Yates Shuffle on Wikipedia
- Doing the Microsoft Shuffle: Algorithm Fail in Browser Ballot
- knuth-shuffle on NPM
'nuf said.
As Microsoft learned the hard way (see article below), function random() { return 0.5 - Math.random() }
turns out to be no-so-random at all.
The fisher-yates shuffle is an algorithm so simple that even IEEE floating point math can't screw it up!
I put this on npm as knuth-shuffle
because fisher-yates-shuffle
was just too long of a name and shuffle was already taken.
<script src="https://raw.github.com/coolaj86/knuth-shuffle/master/index.js"></script>
(function () {
'use strict';
var a = [2,11,37,42];
var b;
// The shuffle modifies the original array
// calling a.slice(0) creates a copy, which is assigned to b
b = window.knuthShuffle(a.slice(0));
console.log(b);
}());
Decentralized Install
npm install --save git+https://git.coolaj86.com/coolaj86/knuth-shuffle.js.git#v1.0
Centralized Install
npm install --save [email protected]
(function () {
'use strict';
var shuffle = require('knuth-shuffle').knuthShuffle;
var a = [2,11,37,42];
var b;
// The shuffle modifies the original array
// calling a.slice(0) creates a copy, which is assigned to b
b = shuffle(a.slice(0));
console.log(b);
}());