React中利用map函数高效渲染嵌套数组（Sub-Array）内容的完整教程

{
  imageUrl: "...",
  user: "...",
  likes: 410,
  caption: "...",
  profilepic: "...",
  comments: [
    {
      user: "zoraiz",
      comment: "Nicee!"
    },
    {
      user: "asher",
      comment: "Alrightttt!!"
    },
    {
      user: "hamis",
      comment: "Interesting...."
    }
  ]
}

class Postcomment2 extends React.Component {
  uploadcomment = () => {
    // 错误尝试：试图通过字符串键访问数组元素，且未正确使用map回调参数
    return this.props.post.comments.map((commentz) => {
      return <div>{this.props.post.comments["comment"]}</div>;
    });
  };

  render() {
    return (
      <div>
        <div>{this.uploadcomment()}</div>
      </div>
    );
  }
}

import React from 'react';

// 假设这是从外部传入的post数据
const samplePost = {
  imageUrl: "https://i.pinimg.com/originals/83/6c/8a/836c8a66349fecbc0a06c4cc3d41e031.jpg",
  user: "sampleUser",
  likes: 410,
  caption: "Here at kingdom tower...",
  profilepic: "...",
  comments: [
    {
      user: "zoraiz",
      comment: "Nicee!",
      id: 1 // 添加一个唯一ID作为key
    },
    {
      user: "asher",
      comment: "Alrightttt!!",
      id: 2
    },
    {
      user: "hamis",
      comment: "Interesting....",
      id: 3
    }
  ]
};

class PostComments extends React.Component {
  // 方法名改为更具描述性的 renderComments
  renderComments = () => {
    // 使用解构赋值，使代码更简洁易读
    const { comments } = this.props.post;

    // 检查comments是否存在且为数组，防止运行时错误
    if (!comments || !Array.isArray(comments) || comments.length === 0) {
      return <p>暂无评论。</p>;
    }

    // 使用map遍历comments数组，并为每个评论返回一个JSX元素
    return comments.map((commentItem) => {
      // React列表渲染时，每个子元素都应该有一个唯一的'key' prop
      // 这里的commentItem就是数组中的每一个评论对象
      return (
        <div key={commentItem.id} style={{ marginBottom: '5px' }}>
          <strong>{commentItem.user}:</strong> {commentItem.comment}
        </div>
      );
    });
  };

  render() {
    return (
      <div style={{ border: '1px solid #eee', padding: '10px', borderRadius: '5px' }}>
        <h3>评论列表:</h3>
        {/* 调用renderComments方法来渲染评论 */}
        {this.renderComments()}
      </div>
    );
  }
}

// 示例用法（在实际应用中，PostComments组件会作为子组件被使用）
function App() {
  return (
    <div>
      <h1>帖子详情</h1>
      {/* 将samplePost作为props传递给PostComments组件 */}
      <PostComments post={samplePost} />
    </div>
  );
}

export default App;