在fetch中更新时，将CSS类添加到React DOM元素

import React, { useState } from 'react';

function MyComponent() {
  const [className, setClassName] = useState('');

  const fetchData = () => {
    // 发起网络请求
    fetch('https://example.com/api/data')
      .then(response => response.json())
      .then(data => {
        // 更新CSS类
        setClassName('updated-class');
      })
      .catch(error => {
        console.error('Error:', error);
      });
  };

  return (
    <div className={className}>
      <button onClick={fetchData}>Fetch Data</button>
    </div>
  );
}

export default MyComponent;