将函数/状态变量传递给React组件(箭头表示法)

// 父组件
import React from 'react';
import ChildComponent from './ChildComponent';

class ParentComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0
    };
  }

  incrementCount = () => {
    this.setState(prevState => ({
      count: prevState.count + 1
    }));
  }

  render() {
    return (
      <div>
        <ChildComponent 
          count={this.state.count} 
          incrementCount={this.incrementCount} 
        />
      </div>
    );
  }
}

// 子组件
import React from 'react';

const ChildComponent = (props) => {
  return (
    <div>
      <p>Count: {props.count}</p>
      <button onClick={props.incrementCount}>Increment</button>
    </div>
  );
}

export default ChildComponent;