滚动时React计数

import React, { Component } from 'react';

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

  componentDidMount() {
    window.addEventListener('scroll', this.handleScroll);
  }

  componentWillUnmount() {
    window.removeEventListener('scroll', this.handleScroll);
  }

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

  render() {
    return (
      <div>
        <p>滚动次数：{this.state.count}</p>
      </div>
    );
  }
}

export default ScrollCounter;