1. 在函数组件实现跨组件通信的方式
2. 注册Context将value传递给子组件let MyContext = React.createContext('默认值');
<MyContext.Provider value={} >
let value = useContext(MyContext)
<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title><style></style><script src="../react.development.js"></script><script src="../react-dom.development.js"></script><script src="../babel.min.js"></script><script src="../lodash.min.js"></script>
</head><body><div id="app"></div><script type="text/babel">let Welcome = (props) => { return (<div>hello Welcome<MyContext.Provider value="welcome的问候~~~"><Head /></MyContext.Provider></div>);}let Head = () => {return (<div>hello Head<Title /></div>);}let Title = () => {let value = useContext(MyContext);return (<div>hello Title, { value }</div>);}let element = (<Welcome />);root.render(element);</script>
</body></html>
