Change Array by Copy: Four New Non-Destructive Array Methods in JavaScript

When working with arrays in JavaScript, one common challenge is ensuring that array manipulations do not affect the original array. This is especially important when working with state management in applications like React or Redux, where immutability is crucial. In JavaScript, the typical array methods like push(), pop(), shift(), and unshift() modify the original array, which can lead to unintended side effects.

Fortunately, recent additions to JavaScript provide non-destructive (or immutable) methods that allow you to create a new array with changes applied, leaving the original array intact. These methods are ideal for when you want to update or manipulate arrays without altering the original reference.

In this tutorial, we will explore four of these new non-destructive array methods introduced in ES6 and beyond: Array.prototype.concat(), Array.prototype.slice(), Array.prototype.map(), and Array.prototype.filter().

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1. concat() – Concatenating Arrays without Modifying the Original

The concat() method is used to merge two or more arrays into a new array. It does not change the original arrays, making it non-destructive.