Add minimize DOM access tip

blog_posts/javascript-store-dom-items.md

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+---
+title: "Tip: Minimize DOM access"
+type: tip
+tags: javascript,browser
+authors: chalarangelo
+cover: blog_images/armchair.jpg
+excerpt: Increase your JavaScript code's performance when working with the DOM by leveraging this simple trick.
+---
+
+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.
+
+**Image credit:** [Amin Hasani](https://unsplash.com/@aminhasani?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText) on [Unsplash](https://unsplash.com?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText)