反应并重新定义this.props.posts未定义?

我试着跟随一个教程,比如一个带有react和redux的博客,但是在 PostList 我在reducer的绑定上有错误,我只想呈现函数 renderPost 使用 map 属于 posts

我的代码中有什么错误?

这是我的组件 邮政名单 :

import React from 'react';
import {connect } from 'react-redux';
import {cargaPost} from '../acciones/index';
import {Link} from 'react-router-dom';
class ListaPost extends React.Component {
    componentWillMount() {
        this.props.fetchPost();
    }
    renderPost () {
        return this.props.posts.map( post => {
            <li className="list-group-item" key={post.id}>
                <span className="text-right">{post.categories}</span>
            </li>
        })
    }
    render() { 
        // const { posts } = this.props;
        // if (!posts) {
        //   return <div>Loading...</div>
        // }
        return (
            <div>
                <div className="text-right">
                    <Link
                    to="/posts/new" 
                    >
                    <button 
                    type="button" 
                    className="btn btn-info">
                    Nuevo Post
                    </button>

                    </Link>
                </div>

                <ul className="list-group">
                    {this.renderPost()}
                </ul>
            </div>
        )
    }
}
function mapStateToProps(state) {
  return { posts: state.todos }
}
export default connect(mapStateToProps, {fetchPost: cargaPost})(ListaPost);

还有我的 减速柱

import {FETCH_POST} from '../acciones/index';

const estadoInicial = { todos:[], unPost: null }
// PostReducer
export default function(state=estadoInicial, accion) {
    switch(accion.type) {
        case FETCH_POST:
            return {...state, todos: accion.payload.data }
        default:
            return state;
    }
}

我的 指数 文件

import {combineReducers} from 'redux';
import PostReducer from './PostReducer';

const rootReducer = combineReducers({
    posts: PostReducer
});

export default rootReducer;