• 用以下三种方式创建 Ref 都可以

import React from 'react'export default function Count () {const [count ,setCount] = React.useState(0)const myRef = React.createRef()const myRef2 = React.useRef()	// Ref Hook 的方式const myRef3 = {current: undefined}const addNumber = () => {setCount(count => count + 1)}const showCount = () => {console.log(myRef3.current.innerText)}return (<div><h2 ref={myRef3}>当前和为 {count}</h2><button onClick={addNumber}>+1</button><button onClick={showCount}>显示和</button></div>)
}