react hooks useContext 实现父子组件通讯

今天接触了一下 hooks , 确实感觉相比 class 组件要轻量及很多,瞬间爱上了~
我来说一下使用 useContext 时实现父子组件通讯问题,贴上我demo的代码~
先贴上我用到的三个文件

父组件 App.js

import React, { useState } from 'react'
import CountContext from './CountContext'
import Counter from './Counter'

export default function App() {
  const [ count, setCount ] = useState(0)
  return (
    <div>
      <p>计数器值为： { count }</p>
      <button onClick={ () => setCount(count+1)}>点我加一</button>
      <CountContext.Provider value={count}>
        <Counter />
      </CountContext.Provider>
    </div>
  )
}

子组件 Counter.jsx

import React, { useContext } from 'react'
import CountContext from './CountContext'

export default function Counter() {
  let count = useContext(CountContext)
  return (
    <h2>{count}</h2>
  )
}

公共组件 CountContext.jsx

import { createContext } from "react";

const CountContext = createContext(null)
export default CountContext