react 18.0.0 版本生命周期

react18版本生命周期

组件挂载时

• constructor
• static getDerivedStateFromProps（纯函数，静态方法）
• render
• componentDidMount

数据更新时

• static getDerivedStateFromProps
• shouldComponentUpdate
• render
• getSnapshotBeforeUpdate
• componentDidUpdate

组件卸载时

• componentWillUnmount

捕获父子组件异常时

• componentDidCatch

新增生命周期

• static getDerivedStateFromProps
• getSnapshotBeforeUpdate

从v16.3开始弃 componentWillMount、componentWillReceiveProps 、componentWillUpdate 三个钩子函数

import React, { Component } from 'react'

export default class index extends Component {
    constructor(props) {
        console.log("constructor============1");
        super();
        this.state = {
            msg: '这是更新前'
        }
    }
    componentDidMount() {
        console.log("componentDidMount=========================3");
    }
    componentDidUpdate() {
        console.log('更新时');
    }
    componentWillUnmount() {
        console.log('卸载时');
    }
    componentDidCatch() {
        console.log("捕捉到异常了");
    }
    static getDerivedStateFromProps(nextProps, prevState) {
        console.log(nextProps, prevState, "纯函数,静态方法");
        return null
    }
    getSnapshotBeforeUpdate(prevProps, prevState) {
        console.log(prevProps, prevState, "需要搭配 componentDidUpdate来使用");
        return null
    }
    shouldComponentUpdate() {
        console.log('是否更新当前组件数据');
        return false
    }
    setDate = () => {
        this.setState({
            msg: '这是更新后'
        })
    }
    render() {
        console.log("render====================2");
        return (
            

                {this.state.msg}
            
        )
    }
}