react组件的参数怎样定义的（详解React中组件之间通信的方式）

function EmailInput(props) {
  return (
    <label>
      Email: <input value={props.email} />
    </label>
  );
}

const element = <EmailInput email="123124132@163.com" />;

class Parents extends Component {
  constructor() {
    super();
    this.state = {
      price: 0
    };
  }

  getItemPrice(e) {
    this.setState({
      price: e
    });
  }

  render() {
    return (
      <li>
        <li>price: {this.state.price}</li>
        {/* 向子组件中传入一个函数  */}
        <Child getPrice={this.getItemPrice.bind(this)} />
      </li>
    );
  }
}

class Child extends Component {
  clickGoods(e) {
    // 在此函数中传入值
    this.props.getPrice(e);
  }

  render() {
    return (
      <li>
        <button onClick={this.clickGoods.bind(this, 100)}>goods1</button>
        <button onClick={this.clickGoods.bind(this, 1000)}>goods2</button>
      </li>
    );
  }
}

class Parent extends React.Component {
  constructor(props) {
    super(props)
    this.state = {count: 0}
  }
  setCount = () => {
    this.setState({count: this.state.count + 1})
  }
  render() {
    return (
      <li>
        <SiblingA
          count={this.state.count}
        />
        <SiblingB
          onClick={this.setCount}
        />
      </li>
    );
  }
}

 const PriceContext = React.createContext('price')

class MyClass extends React.Component {
  static contextType = PriceContext;
  render() {
    let price = this.context;
    /* 基于这个值进行渲染工作 */
  }
}

<PriceContext.Consumer>
    { /*这里是一个函数*/ }
    {
        price => <li>price：{price}</li>
    }
</PriceContext.Consumer>