useLayoutEffect Hooks
The useLayoutEffect hook in React is a tool that allows you to perform side effects synchronously after the DOM has been updated but before the browser has repainted the screen.
- Synchronous Execution: Unlike useEffect, which runs asynchronously after the browser paints, useLayoutEffect executes synchronously immediately after the DOM has been updated but before the browser has a chance to paint the changes on the screen.
- Performance Considerations: Since useLayoutEffect runs synchronously, it can potentially cause performance issues, especially if it involves computationally expensive tasks or triggers additional renders. It’s crucial to use useLayoutEffect thoughtfully and consider if useEffect might be a more suitable choice for your specific use case.
Syntax:
useLayoutEffect(setup, dependencies)
or
useLayoutEffect(()=> // some code to execute , dependency //e.g. [] if none)
Example: Below is an example of useLayoutEffect Hooks.
Javascript
// App.jsimport React, { useLayoutEffect, useState} from "react";const App = () => { const [value, setValue] = useState("GFG"); useLayoutEffect(() => { console.log( "UseLayoutEffect is called with the value of ", value ); }, [value]); setTimeout(() => { setValue("w3wiki"); }, 2000); return ( <div style={{ textAlign: "center", margin: "auto", }} > <h1 style={{ color: "green" }}>{value}</h1> is the greatest portal for geeks! </div> );};export default App; |
Output:
Output
Effect Hooks in React
Effect Hooks in React allow components to interact with and stay synchronized with external systems, such as handling network requests, manipulating the browser’s DOM, managing animations, integrating with widgets from other UI libraries, and working with non-React code. Essentially, effects help components communicate and coordinate with the world outside of React.
- useEffect is used to connect components to an external system.
- useLayoutEffect performs a side effect immediately after the browser has painted the screen.
- useInsertionEffect is used before ReactJS makes changes to the DOM, and in this libraries can insert the dynamic CSS.
We will discuss about the following types of Effect Hooks in React.
Table of Content
- useEffect Hooks
- useLayoutEffect Hooks
- useInsertionEffect Hooks