그리고 PostList에서 받아 온 props에 따라 결과물을 보여 주세요.

components/posts/PostList.js

import React from 'react';
import styled from 'styled-components';
import { Link } from 'react-router-dom';
import Responsive from '../common/Responsive';
import Button from '../common/Button';
import palette from '../../lib/styles/palette';
import SubInfo from '../common/SubInfo';
import Tags from '../common/Tags';

(...)

const PostItem = ({ post }) => {
  const { publishedDate, user, tags, title, body, _id } = post;
  return (
    <PostItemBlock>
      <h2>
        <Link to={`/@${user.username}/${_id}`}>{title}</Link>
      </h2>
      <SubInfo
        username={user.username}
        publishedDate={new Date(publishedDate)}
      />
      <Tags tags={tags} />
      <p>{body}</p>
    </PostItemBlock>
  );
};

const PostList = ({ posts, loading, error, showWriteButton }) => {
  // 에러 발생 시
  if (error) {
    return <PostListBlock>에러가 발생했습니다.</PostListBlock>;
  }

  return (
    <PostListBlock>
      <WritePostButtonWrapper>
        {showWriteButton && (
          <Button cyan to="/write">
            새 글 작성하기
          </Button>
        )}
      </WritePostButtonWrapper>
      {/*  로딩 중이 아니고, 포스트 배열이 존재할 때만 보여 줌 */}
      {!loading && posts && (
        <div>
          {posts.map(post => (
            <PostItem post={post} key={post._id} />
          ))}
        </div>
      )}
    </PostListBlock>
  );
};

export default PostList;

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