react生命周期(类组件/函数组件)操作代码_React

import React from 'react'
export default class App1 extends React.Component{
    state = {
        username:'',
        password:''
    }
    setUser = (event) => {
        this.setState({username:event.target.value})
    }
    setPass = (event) => {
        this.setState({password:event.target.value})
    }
    Submit = () => {
        console.log(this.state.username , this.state.password)
    }
    render(){
        return(
            <>
              <input type="text" value={this.state.username} onChange={this.setUser}/>
              <input type="text" value={this.state.paddword} onChange={this.setPass}/>
              <button onClick={this.Submit}>登录</button>
            </>
        )
    }
}

import { useState ,useEffect} from "react"
function App1 (){
    const [username ,setUsername] = useState('')
    const [password ,setPassword] = useState('')
    const setChange = event => {
        setUsername(event.target.value);
      };
      const setChangePassWold = event => {
        setPassword(event.target.value);
      };
      const Submit = () =>{
          console.log(username,password)
      }
    return(
        <>
         <input value={username} onChange={setChange}></input>
         <input value={password} onChange={setChangePassWold}></input>
         <button onClick={Submit}>登录</button>
        </>
    )
}
export default  App1

import React  from "react";
import {Link} from 'react-router-dom'
class Demo extends React.Component{
  
    constructor(props){
        super(props)
        console.log("constructor")
    }
    state = {
        num:1
    }
    UNSAFE_componentWillMount(){
        console.log("componentWillMount")
    }
    componentDidMount(){
        console.log("componentDidMount")
    }
    shouldComponentUpdate(){
      console.log('shouldComponentUpdate')
      return true
    }
    UNSAFE_omponentWillUpdate(){
        console.log("componentWillUpdate")
    }
    componentDidUpdate(){
        console.log("componentDidUpdate")
    }
    componentWillUnmount(){
        console.log("componentWillUnmount")
    }
    Submit = () =>  {
        this.setState({num:this.state.num+=1})
    }
    render(){
        console.log('render')
        return(
            <>
              <Link to='/app1'>App1</Link>
              //这里替换成自己的即可
              <h3>{this.state.num}</h3>
              <button onClick={this.Submit}>改变</button>
            </>
        )
    }
}
export default Demo

import { useState ,useEffect} from "react"
import {Link} from 'react-router-dom'
function App1 (){
    const [username ,setUsername] = useState('')
    const [password ,setPassword] = useState('')
    const setChange = event => {
        setUsername(event.target.value);
      };
      const setChangePassWold = event => {
        setPassword(event.target.value);
      };
      const Submit = () =>{
        setUsername('')
          console.log(username,password)
      }
        // useEffect  =  vue mounted 区别是只要视图更新就变化 感觉类似watch 但是他又是初始化的 时候第一个
        //  useEffect(()=>{},[])
        useEffect(()=>{
          console.log('模拟componentDidMount第一次渲染')
            return () =>{
                console.log('模拟componentWillUnmount执行销毁后')
            }
        },[password])
    return(
        <>
          <Link to='/home1'>home1</Link>
            //这里需要修改成自己的路径
          <input value={username} onChange={setChange}></input>
          <input value={password} onChange={setChangePassWold}></input>
          <button onClick={Submit}>登录</button>
        </>
    )
}
export default  App1