29 lines
1.4 KiB
Markdown
29 lines
1.4 KiB
Markdown
---
|
|
title: "Tip: Minimize DOM access"
|
|
shortTitle: Minimize DOM access
|
|
type: tip
|
|
tags: javascript,browser
|
|
author: chalarangelo
|
|
cover: blog_images/armchair.jpg
|
|
excerpt: Increase your JavaScript code's performance when working with the DOM by leveraging this simple trick.
|
|
firstSeen: 2020-11-20T09:18:55+02:00
|
|
lastUpdated: 2021-06-12T19:30:41+03:00
|
|
---
|
|
|
|
DOM operations, including accessing the DOM, are generally slow. This is usually not a problem until you have to perform many DOM operations and your JavaScript application's performance starts to suffer. A very quick trick to increase performance is to store DOM elements or their values in local variables if you plan to access them multiple times.
|
|
|
|
```js
|
|
// This is slow, it accesses the DOM element multiple times
|
|
document.querySelector('#my-element').classList.add('my-class');
|
|
document.querySelector('#my-element').textContent = 'hello';
|
|
document.querySelector('#my-element').hidden = false;
|
|
|
|
// This is faster, it stores the DOM element in a variable
|
|
const myElement = document.querySelector('#my-element');
|
|
myElement.classList.add('my-class');
|
|
myElement.textContent = 'hello';
|
|
myElement.hidden = false;
|
|
```
|
|
|
|
Note that, while this trick may come in handy, it comes with the caveat that if you later remove the DOM element and you still have it stored in a variable, the variable should be set to `null` to avoid potential memory leaks.
|