How to prevent subcomponents from rendering in react-Front-end Q&A-php.cn

React method to prevent child components from rendering: 1. Use "shouldComponentUpdate(nextProps,nextState){...}" to achieve parent component rendering and child components not to render; 2. Use "PureComponent" to prevent child components from rendering. The component does not render; 3. Introduce memo and wrap the hooks with memo.

How to prevent subcomponents from rendering in react

The operating environment of this tutorial: Windows 10 system, react18.0.0 version, Dell G3 computer.

How to prevent child components from rendering in react?

React parent component re-renders and child components do not need to be rendered. Three performance optimization methods (PureComponent, memo, shouldComponentUpdate);

//When using React ordinary functions, you can use Two optimization methods, PureComponent and shouldComponentUpdate

//shouldComponentUpdate

//shouldComponentUpdate class Foo extends Component { shouldComponentUpdate(nextProps,nextState){ if(nextProps.count===this.props.count){ //传入的count与组件当前props的count比较,count没改变，return false，不渲染 return false //不渲染 } return true; //渲染 } render() { console.log("组件渲染"); //可以看到，当父组件的name改变时，子组件不会打印，只有count改变，才会打印，优化性能 return null } } class App extends Component { state = { count: 0, name: 0 } render() { return (      ) } }

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//PureComponent

//引入PureComponent import React, { Component, Fragment, PureComponent} from 'react'; //PureComponent，自动比较组件数据是否改变，注意只能比较一层，比如一个对象，对象中的属性改变，他不会重新渲染，只有对象改变，才重新渲染。 class Foo extends PureComponent { render() { console.log("组件渲染"); return null } } class App extends Component { state = { count: 0, name: 0 } render() { return (      ) } }

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//hooks Unique optimization method memo

//引入memo import React, { Component, Fragment, memo } from 'react'; //用memo把hooks包裹即可 const Foo = memo(function Foo(props) { console.log("组件渲染"); return count:{props.count}
 }) class App extends Component { state = { count: 0, name: 0 } render() { return (      ) } }

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