React 学习笔记 —— Ref Hook

• 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>
    )
}