需要帮助了解此代码如何通过ReactJS访问reddit API中的数据

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

const RedditData = () => {
  const [data, setData] = useState([]);

  useEffect(() => {
    const fetchData = async () => {
      const response = await fetch('https://www.reddit.com/r/javascript.json');
      const json = await response.json();
      setData(json.data.children);
    };

    fetchData();
  }, []);

  return (
    <div>
      <h1>Reddit Data</h1>
      <ul>
        {data.map((post) => (
          <li key={post.data.id}>{post.data.title}</li>
        ))}
      </ul>
    </div>
  );
};

export default RedditData;