小编eda*_*med的帖子

我将类组件更改为功能组件并使用钩子和 useEffect 所以我的应用程序变得非常缓慢并且没有任何错误

import React, { useState, useEffect } from 'react';
import Toolbar from '@material-ui/core/Toolbar';

const FancyToolBar = ({ children }) => {
  const [backGround, togglebackGround] = useState('white');
  const listenScrollEvent = () => {
    if (window.scrollY > 80) {
      togglebackGround('black');
    } else {
      togglebackGround('white');
    }
  };
  useEffect(() => {
    window.addEventListener('scroll', listenScrollEvent);
  });
  const logo = backGround === 'white'
    ? <img src="/images/1.jpg" alt="" style={{ width: '50px !important', height: '50px' }} />
    : <img src="/images/2.png" alt="" style={{ width: '50px !important', height: '50px' …