React Redux 中的状态未正确更改答案

【问题标题】：State Not Changing Properly In React ReduxReact Redux 中的状态未正确更改
【发布时间】：2019-04-30 18:18:33
【问题描述】：

我是 React Redux 的新手，我已经初始化了状态，通过调用其各自的 reducer 来正确显示哪个作业返回初始化状态。但是在改变状态之后，状态很可能没有改变，我不知道为什么

import { combineReducers } from 'redux';

const initialState = {
    songs:[
        {title:'No Scrubs', duration: '4:05'},
    ]
}

const songReducers = (state = initialState)=>{
    return state
}

const selectedSongReducer =(selectedSong=null,action)=>{
    if(action.type==='SONG_SELECTED'){
        return action.payload
    }

    return selectedSong;
}


const addSongReducer = (state=initialState,action)=>{
    if(action.type==="ADD_SONG"){
       return {
        ...state,   
        songs:[
           ...state.songs, {title:'All demo', duration: '4:05'}
        ]
    }
    }
    return state;
}

export default combineReducers({
    songs: songReducers,
    selectedSong: selectedSongReducer,
    addSong:addSongReducer
})

【问题讨论】：

标签： reactjs redux react-redux

【解决方案1】：

你的整体状态形状看起来像

state = {
    songs: {
        songs: [
            { title: 'No Scrubs', duration: '4:05' },
        ]
    },
    selectedSong: null,
    addSong: {
        songs: [
            { title: 'No Scrubs', duration: '4:05' },
        ]
    }
}

在第一次 reducer 调用之后。这是你想要的吗？因为你有所以问

state = {
    songs: {
        songs: [
            { title: 'No Scrubs', duration: '4:05' },
        ]
    },
    ...
}

而不仅仅是

state = {
    songs: [
        { title: 'No Scrubs', duration: '4:05' },
    ]
    ...
}

【讨论】：