How can I clone an array in JavaScript?

Angelos Chalaris · JavaScript, Array · Jun 12, 2021

JavaScript provides quite a few ways to clone an array, most of which are pretty similar in terms of performance and results. Here's a quick rundown of some of the available options.

The spread operator

ES6 introduced the spread operator (...), which provides probably the easiest and most common way to create a shallow clone of an array.

let x = [1, 2, 3, 4];
let y = [...x];


Array.from() has a very powerful API that can be used for many different things, including creating a copy of an array.

let x = [1, 2, 3, 4];
let y = Array.from(x);


Similarly to the spread operator, Array.prototype.slice() can be used to create a shallow copy of an array.

let x = [1, 2, 3, 4];
let y = x.slice();

Looking into one of the more unorthodox options, can be used to map each element of an array to itself to create a new array.

let x = [1, 2, 3, 4];
let y = => i);


Similarly, Array.prototype.filter() can be used to return true for each and every element, resulting in a new array with all of the original array's elements.

let x = [1, 2, 3, 4];
let y = x.filter(() => true);


Finally, Object.assign() can be used in the exact same way as it's used to create a clone of an object, but for an array instead.

let x = [1, 2, 3, 4];
let y = Object.assign([], x);

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