PostList.js

import React, { Component, Fragment } from 'react'
import { connect } from 'react-redux'
import { handleGetAllPosts } from '../actions/posts'

class PostList extends Component {
  componentDidMount () {
    this.props.getAllPosts()
  }
  render() {
    const { posts } = this.props
    return (
      <Fragment>
        {Object.keys(posts).map(postId =>
          <p key={postId}>{posts[postId].title}</p>
        )}
      </Fragment>
    )
  }
}

const mapDispatchToProps = {
  getAllPosts: handleGetAllPosts,
}

function mapStateToProps ({ posts }) {
  return {
    posts,
  }
}

export default connect(mapStateToProps, mapDispatchToProps)(PostList)