我遇到了一个无法解决的错误。我正在建立一个博客网站作为一个副项目。现在，我正在尝试呈现单个帖子，但是当我尝试访问对象属性时，我收到错误 TypeError：无法读取属性“title”为null 。我不明白为什么对象属性为null，尽管我可以打印对象本身。以下是代码片段：

这是一个 PostView 组件，它将处理帖子内容的呈现。我可以在控制台中打印从 api 收到的帖子对象，但是当我尝试访问或打印其属性（如标题、正文等）时...我收到错误。起初我以为我在 redux Reducer 和操作中遇到了错误，但似乎它运行良好。状态正在改变，我收到了 json 响应。我对其他组件使用了类似的代码，并且成功了，所以我不明白我哪里犯了错误？

import React, {useEffect, useState } from 'react';
import PropTypes from 'prop-types';
import { connect } from 'react-redux';
import { getPost} from 'actions/post';

//Components
import PostContent from '../Content/PostContent';

//Material Ui 
import { Grid } from '@material-ui/core';
import { useStyles } from '@material-ui/core/styles';




const PostView = ({ getPost, post: {post: { title, body, category }, loading }, match}) => {
    useEffect(() => {
        getPost(match.params.id);
    },[getPost]);
    
    //This code works
    console.log(post);
    //But this one does not
    console.log(post.title);

    return (
            <Grid container>
                <PostContent/>
            </Grid>
    )
}

PostView.propTypes = {
    getPost: PropTypes.func.isRequired,
    post: PropTypes.object.isRequired,
}

const mapStateToProps = (state) => ({
    post: state.post
});

export default connect(mapStateToProps, { getPost })(PostView)

这也是我的动作函数：

//Get Post by Id
export const getPost = (id) => async dispatch => {
    try {
        const res = await axios.get(`/api/posts/${id}`);
        dispatch({
            type: GET_POST,
            payload: res.data
        });
    }catch(err){
        dispatch({
            type: POST_ERROR,
            payload: {msg: err.response.statusText, status: err.response.status}
        });
    }

};

以及帖子 Reducer 文件：

import{
    GET_POSTS,
    POST_ERROR,
    UPDATE_VOTES,
    ADD_POST,
    GET_POST,
    GET_POSTS_IMAGE,
    POSTS_IMAGE_ERROR
} from '../actions/types';


const initialState = {
    posts: [],
    post: null,
    loading: true,
    status: true,
    error: {}
}



export default function(state = initialState, action) {
    const { type, payload } = action;

    switch (type) {
        case GET_POSTS:
            return{
                ...state, 
                posts: payload,
                loading: false
            };
        case POST_ERROR:
            return{
                ...state, 
                error: payload,
                loading: false
            } ;
        case UPDATE_VOTES:
            return{
                ...state,
                posts: state.posts.map(post => post._id === payload.postId ? { ...post, upVotes: payload.upVotes} : post),
                loading: false
            };  
        case ADD_POST:
            return{
                ...state,
                posts: [...state.posts, payload],
                loading: false,
                status: false
            };
        case GET_POST:
            return{
                ...state,
                post: payload,
                loading: false
            }
        default:
            return state;
    }
}

我只学习 React 和 Redux，因此任何帮助都将不胜感激。 strong text