Post.jsx

import React, { Component } from 'react';
//import { ProviderTypes } from 'react-redux';
import './Post.css';

class Post extends Component {
  constructor(props) {
    super(props);
    this.props = props;
  }

  render() {
    return (
      <div key={this.props.item_key} className="Post">
        <h4>{this.props.user.toUpperCase()}</h4>
        <div className="image-container">
          <img alt="post" src={this.props.image} />
          <div className="voting">
            <i className="material-icons yes">keyboard_arrow_up</i>
            <i className="material-icons no">keyboard_arrow_down</i>
          </div>
        </div>
        <p>{this.props.text}</p>
      </div>
    );
  }
}

// <p><span>{this.props.user.toUpperCase()}</span>{this.props.text}</p>

export default Post;

PostList.jsx

import React, { Component } from 'react';
import { connect/*, ProviderTypes*/ } from 'react-redux';
import Post from './Post';
import './PostList.css';

class PostList extends Component {
  constructor(props) {
    super(props);
    this.props = props;
  }

  render() {
    return (
      <div className="PostList">
        {
          this.props[this.props.tag].map((item) => {
            return(
              <Post
                item_key={item.key}
                key={item.key}
                user={item.user}
                image={item.image}
                text={item.text}
              />
            );
          })
        }
      </div>
    );
  }
}

const mapStateToProps = (state) => {
  return state.posts;
}

PostList = connect(mapStateToProps)(PostList);

export default PostList;