28 lines
1.3 KiB
Markdown
28 lines
1.3 KiB
Markdown
---
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title: "Tip: Minimize DOM access"
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shortTitle: Minimize DOM access
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type: tip
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tags: [javascript,browser]
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author: chalarangelo
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cover: armchair
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excerpt: Increase your JavaScript code's performance when working with the DOM by leveraging this simple trick.
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dateModified: 2021-06-12T19:30:41+03:00
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---
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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.
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```js
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// This is slow, it accesses the DOM element multiple times
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document.querySelector('#my-element').classList.add('my-class');
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document.querySelector('#my-element').textContent = 'hello';
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document.querySelector('#my-element').hidden = false;
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// This is faster, it stores the DOM element in a variable
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const myElement = document.querySelector('#my-element');
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myElement.classList.add('my-class');
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myElement.textContent = 'hello';
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myElement.hidden = false;
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```
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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.
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