How can I clone an array in JavaScript?

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.
ES6 introduced the spread operator (...), which provides probably the easiest and most common way to create a shallow clone of an array.
Array.from() has a very powerful API that can be used for many different things, including creating a copy of an array.
Similarly to the spread operator, Array.prototype.slice() can be used to create a shallow copy of an array.
Looking into one of the more unorthodox options, Array.prototype.map() 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 = [...x];

Array.from() has a very powerful API that can be used for many different things, including creating a copy of an array.
Similarly to the spread operator, Array.prototype.slice() can be used to create a shallow copy of an array.
Looking into one of the more unorthodox options, Array.prototype.map() can be used to map each element of an array to itself to create a new array.
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.
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.
<baseline-support featureId="structured-clone">

From 30-seconds-of-code: copy-array