copy an array javascript

When working with data in JavaScript, you might often need to duplicate an array for various reasons. This article will guide you through a simple and common way to copy an array in JavaScript.

Code snippet for copying an array

let originalArray = [1, 2, 3, 4, 5];
let copiedArray = [...originalArray];

Code Explanation for copying an array

In this simple example, we used the spread operator to copy an array in JavaScript. Below are the steps explaining how this worked.

Step 1: We initiate an array and assign it to a variable called originalArray.

let originalArray = [1, 2, 3, 4, 5];

Step 2: We declare another variable copiedArray. Here is the part where the actual copying of the array happens. The [...originalArray] syntax is using the spread operator (...).

let copiedArray = [...originalArray];

The spread operator takes all values from the originalArray and spreads them into the new, copiedArray. What you end up with is a new array containing all elements from the original array, effectively creating a copy of the original.

Now, if we change the values in the originalArray, it will not affect the copiedArray because they are two different arrays in memory. This is how you can successfully create a copy of an array in JavaScript.

Keep in mind that this method only creates a shallow copy of the array. Meaning, it will work perfectly with arrays containing primitive data types (Number, String, Boolean), but for arrays with objects, it will only copy the reference to the objects. If the objects are mutated, those changes can be reflected in both arrays. For copying arrays with objects, a method of deep cloning is required. That, however, is a topic of another discussion.

This JavaScript strategy of array copying is a staple in the software development industry and plays a significant role in dealing with data manipulation.