qq_43341001的博客

//这个就直接采用函数式写法，不用类的写法 import React ,{Fragment,useState} from "react" function sheepNi(){ let [num,setNum] = useState(1); const addNum = ()=>{ // setNum(num++);//这种写法就是新值覆盖初始值 setNum(()=>{ //这种写法就是新值覆盖旧值 num++; }) } render(){ return(

import React, { Component, Fragment } from "react"; //采用类的写法，现在在版本16.8以后出现Hooks以后就几乎不用类的写法 export default class App extends Component{ state = { arr:["我的小红书账号sheepNi","喜欢和大家交朋友"] } render(){ return( <> <ul> return( this