42 lines
1.3 KiB
Markdown
42 lines
1.3 KiB
Markdown
---
|
||
title: 3 ways to use the JavaScript spread operator with arrays
|
||
shortTitle: Array tricks using the spread operator
|
||
type: story
|
||
tags: javascript,array
|
||
author: chalarangelo
|
||
cover: blog_images/succulent-crowd.jpg
|
||
excerpt: JavaScript’s spread operator is a very versatile tool. Here are some simple ways to use it.
|
||
firstSeen: 2022-04-17T05:00:00-04:00
|
||
---
|
||
|
||
### Clone an array
|
||
|
||
The spread operator can be used to clone an array into a new array. This trick can come in handy when working with arrays of primitives. However, it only shallow clones the array, meaning nested non-primitive values will not be cloned.
|
||
|
||
```js
|
||
const arr = [1, 2, 3];
|
||
const arr2 = [...arr];
|
||
// [1, 2, 3]
|
||
```
|
||
|
||
### Merge multiple arrays
|
||
|
||
Using the spread operator, it’s possible to combine two or more arrays into one. You should think of this trick as cloning two arrays into a new one. Due to that, the shallow cloning limitation mentioned previously applies here, too.
|
||
|
||
```js
|
||
const arr1 = [1, 2, 3];
|
||
const arr2 = [4, 5, 6];
|
||
const combined = [...arr1, ...arr2];
|
||
// [1, 2, 3, 4, 5, 6]
|
||
```
|
||
|
||
### Add items to an array
|
||
|
||
Similarly to previous tricks, it’s possible to spread an array into a new one and add individual elements, too. This can also be combined with merging multiple arrays, if desired.
|
||
|
||
```js
|
||
const arr = [1, 2, 3];
|
||
const arr2 = [0, ...arr, 4];
|
||
// [0, 1, 2, 3, 4]
|
||
```
|