How to randomize (shuffle) a JavaScript array?

I have an array like this:

var arr1 = ["a", "b", "c", "d"];

How can I randomize / shuffle it?

The de-facto unbiased shuffle algorithm is the Fisher–Yates (aka Knuth) Shuffle.

You can see a great visualization here.



function shuffle(array) {
let currentIndex = array.length;

// While there remain elements to shuffle...
while (currentIndex != 0) {

// Pick a remaining element...
let randomIndex = Math.floor(Math.random() * currentIndex);
currentIndex--;

// And swap it with the current element.
[array[currentIndex], array[randomIndex]] = [
array[randomIndex], array[currentIndex]];
}
}

// Used like so
let arr = [2, 11, 37, 42];
shuffle(arr);
console.log(arr);

Stack Overflow Q#2450954, score: 2621