import React,{createContext} from 'react';
import ReactDOM from 'react-dom';
let {Provider, Consumer}  = createContext();

//统一状态管理
class ProviderComponent extends React.Component{
    render(){
        return (<Provider value={123}>
            {this.props.children}
        </Provider>)
    }
}

class Child extends React.Component{
    render(){
        return (<div>
            <Consumer>
                {(value)=>
                    <h3>{value}</h3>
                }
            </Consumer>
        </div>)
    }
}

class App extends React.Component{
    render(){
        return (<div>
            <Child></Child>
        </div>)
    }
}


ReactDOM.render(
    <ProviderComponent>
        <App />
    </ProviderComponent>
    , document.getElementById('root'));