函数组件
// src/components/Hello1.jsximport { useState } from 'react'function Hello1 () {const [ hello1, setHello1 ] = useState('world1')return (<div>hello1</div>)
}export default Hello1;
类组件
// src/components/Hello2.jsximport React from "react";class Hello2 extends React.Component {constructor(props) {super(props)this.state = {hello2: 'world2'}}render() {return (<div>hello2</div>)}}export default Hello2
