我得到一个地图函数的箭头(posts.map 不是一个函数)

I get an arror for map function(posts.map is not a function)

我收到此错误,但我没有发现其中有任何问题:

posts.map is not a function

import React from 'react'
import { useSelector } from 'react-redux'

export const PostsList = () => {
  const posts = useSelector(state => state.posts)

  const renderedPosts = posts.map(post => (
    <article className="post-excerpt" key={post.id}>
      <h3>{post.title}</h3>
      <p className="post-content">{post.content.substring(0, 100)}</p>
    </article>
  ))

  return (
    <section className="posts-list">
      <h2>Posts</h2>
      {renderedPosts}
    </section>
  )
}

这是我的代码沙盒:https://codesandbox.io/s/wandering-darkness-6hi04d?file=/src/features/posts/PostsList.js

你的问题在文件中store.js

export default configureStore({
  reducer: () => ({
    posts: postsReducer
  })
});

修改此文件如下:

export default configureStore({
  reducer: {
    posts: postsReducer
  }
});