Vanilla JavaScript Shuffle Array

— 3 minute read

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Now and then, you need randomly to shuffle an array in JavaScript. There is a super-easy way of doing so. We can use the sort() method and pass a random number to it.

JavaScript Shuffle Array permalink

As mentioned in the introduction, we are going to be using the sort method.

This method, without any parameters, will sort an array in a natural way like 123 and abc.

See the following example:

var charArray = ['d', 'f', 'a', 'c', 'b', 'e'];
var numArray = [1, 5, 3, 2, 4];

console.log(charArray.sort());
// ["a", "b", "c", "d", "e", "f"]

console.log(numArray.sort());
// [1, 2, 3, 4, 5]

As you can see the Arrays get normalised sorted. But we can also pass a specific argument which is what we are going to use to randomise the sort.

var rockPaperScissor = ['💎', '📄', '✂️'];
console.log(rockPaperScissor.sort(() => 0.5 - Math.random()));

This will randomly shuffle the array let me explain in depth.

The sort function comes with a comparison between two elements, where element one is bigger than two. It will put the index lower or higher.

As for the .5 - Math.random() this will return a value between -0.5 and 0.5

So whenever the value is below 0, the element is placed before the one other element.

Also, read about sorting an Array of Objects by Value

You can test this and see it in action on this Codepen.

See the Pen Vanilla JavaScript Shuffle Array by Chris Bongers (@rebelchris) on CodePen.

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