在useEffect内部获取后，React状态仍未定义

import React, { useEffect, useState } from 'react';

function MyComponent() {
  const [data, setData] = useState(null);
  const [isLoading, setIsLoading] = useState(true);

  useEffect(() => {
    const fetchData = async () => {
      try {
        const response = await fetch('https://api.example.com/data');
        const jsonData = await response.json();
        setData(jsonData);
        setIsLoading(false);
      } catch (error) {
        console.error('Error fetching data:', error);
      }
    };

    fetchData();
  }, []); // 添加一个空数组作为依赖项，表示effect只运行一次

  if (isLoading) {
    return <div>Loading...</div>;
  }

  return <div>{data}</div>;
}

export default MyComponent;