使用CombineReducer后无法访问props [英] Can´t access props after using CombineReducer
问题描述
我之前的 React-Redux 实现是有效的,但是在我尝试使用单独的文件实现 combineReducer 函数之后,抛出了一个我不太理解的错误.希望你们中的一些人可以帮助我!
错误:未捕获的类型错误:this.props.todos.map 不是函数
我对该代码的参考是 Redux-Doc 的异步示例.但是我用另一个例子说明了每个例子的变化都没有记录在文档中.
我将展示的第一个代码是我有(工作):
我的商店
import { createStore, applyMiddleware } from 'redux'从redux-thunk"导入 thunkMiddleware从redux-logger"导入 createLogger从 '../reducers/addItem' 导入 addItem导出默认函数 configureStore(preloadedState) {const store = createStore(新增项目,预加载状态,应用中间件(thunkMiddleware,createLogger()))如果(模块.热){//为 reducer 启用 Webpack 热模块替换module.hot.accept('../reducers', () => {const nextRootReducer = require('../reducers').defaultstore.replaceReducer(nextRootReducer)})}退货商店}
我的减速机
export default (state = ['Test'], action) =>{开关(动作.类型){案例ADD_ITEM"://返回action.item返回 [...状态,{id:action.id,文本:action.item}]默认:返回状态}}
动作
导出默认函数 addItem(item){console.log("addTOdo")返回 {类型:'ADD_ITEM',id: nextTodoId++,物品}}
以及最终渲染输入的子组件
import React, { Component, PropTypes } from 'react'从'react-redux'导入{连接}导出默认类 TodoList 扩展组件 {使成为() {const 帖子 = this.propsconst isEmpty = posts.length === 0返回 (<div><h3>Meine Aufgaben</h3><ul>{是空的?<h3>Sie haben noch keinen Todo´s angelegt</h3>:<h3>Ihre Ergebnisse</h3>}{this.props.todos.map((todo, i) => <li key={i}>{todo.text} </li>)}
)}}const mapStateToProp = state =>({待办事项:状态})导出默认连接(mapStateToProp)(TodoList)
我有什么变化:
首先,我创建了另一个名为 Index 的 Reducers 文件,我在其中导入了 addItem Reducer 并导出了 rootReducer:
从'redux'导入{combineReducers}从 './addItem' 导入 addItem从 './getItem' 导入 getItemconst rootReducer = combineReducers({新增项目,获取项目})导出默认 rootReducer
之后,我更改了 Store 以导入 rootReducer 并将其引用放入 Store(只是对 configureStore 的更改):
从'../reducers/index'导入rootReducerconst store = createStore(根减速器,预加载状态,应用中间件(thunkMiddleware,createLogger()))
我不知道是否也需要该信息,但这是我的容器组件:
import React, { Component, PropTypes } from 'react'从'../components/AddTodo' 导入 AddTodo从 '../components/TodoList' 导入 TodoList从'react-redux'导入{连接}从 '../actions/addItem' 导入 addItem从'../actions/getItems'导入getItems类 App 扩展组件 {构造函数(道具){超级(道具)this.handleClick = this.handleClick.bind(this)this.state = {文本:''}}句柄点击(e){控制台日志(e);const {dispatch} = this.props调度(添加项目(e));}componentDidMount(){console.log("组件安装");const {dispatch} = this.props//调度(getItems())}componentWillReceiveProps(nextProps) {console.log("GETTT IT");控制台日志(nextProps)}使成为() {返回 (<div><h1>你好</h1><AddTodo handleAddItem={this.handleClick}/><待办事项列表/>
)}}App.propTypes = {调度:PropTypes.func.isRequired}函数 mapStateToProps(state){返回 {添加待办事项}}导出默认连接 (mapStateToProps)(App)
我希望这个问题不是基本的,有人可以帮助我.提前致谢!
如果您检查您的 redux 状态,您将看到以下代码在状态中设置了另外 2 个键(addItem
和 getItem
):
const rootReducer = combineReducers({新增项目,获取项目})
因此,现在要连接 todos
,您需要使用 2 个新密钥之一.如果 todos
没有定义在那些上面,那么你需要将 todos
的 reducer 添加到 combineReducers
调用中.
所以这需要映射到状态中的有效位置:
const mapStateToProp = state =>({待办事项:状态})
My previous React-Redux implementation was working, but after I tried to implement the combineReducer function with seperated files, an error is thrown that I don´t really understand. Hope some of you can help me!
ERROR: Uncaught TypeError: this.props.todos.map is not a function
My Reference for that Code was the Async Example of the Redux-Doc´s. But I stated with another example and the change from each examples are not documented in the doc´s.
The first code I will show, is that I had (working):
MyStore
import { createStore, applyMiddleware } from 'redux'
import thunkMiddleware from 'redux-thunk'
import createLogger from 'redux-logger'
import addItem from '../reducers/addItem'
export default function configureStore(preloadedState) {
const store = createStore(
addItem,
preloadedState,
applyMiddleware(thunkMiddleware, createLogger())
)
if (module.hot) {
// Enable Webpack hot module replacement for reducers
module.hot.accept('../reducers', () => {
const nextRootReducer = require('../reducers').default
store.replaceReducer(nextRootReducer)
})
}
return store
}
My Reducer
export default (state = ['Test'], action) => {
switch (action.type){
case 'ADD_ITEM':
//return action.item
return [
...state,
{
id: action.id,
text: action.item
}
]
default:
return state
}
}
Actions
export default function addItem(item){
console.log("addTOdo")
return {
type: 'ADD_ITEM',
id: nextTodoId++,
item
}
}
And the subComponent where the input is finally rendered
import React, { Component, PropTypes } from 'react'
import { connect } from 'react-redux'
export default class TodoList extends Component {
render() {
const posts = this.props
const isEmpty = posts.length === 0
return (
<div>
<h3>Meine Aufgaben</h3>
<ul>
{isEmpty
? <h3>Sie haben noch keinen Todo´s angelegt</h3>
: <h3>Ihre Ergebnisse</h3>
}
{this.props.todos.map((todo, i) => <li key={i}>{todo.text} </li>)}
</ul>
</div>
)
}
}
const mapStateToProp = state => ({todos: state})
export default connect (mapStateToProp)(TodoList)
What I have change:
First, I created another Reducers File, called Index where I imported the addItem Reducer and exported the rootReducer:
import {combineReducers} from 'redux'
import addItem from './addItem'
import getItem from './getItem'
const rootReducer = combineReducers({
addItem,
getItem
})
export default rootReducer
After that, I changed the Store to import the rootReducer and put it´s reference in the Store (just the changes to configureStore):
import rootReducer from '../reducers/index'
const store = createStore(
rootReducer,
preloadedState,
applyMiddleware(thunkMiddleware, createLogger())
)
I don´t know if that Information is also required, but here is my Container Component:
import React, { Component, PropTypes } from 'react'
import AddTodo from '../components/AddTodo'
import TodoList from '../components/TodoList'
import { connect } from 'react-redux'
import addItem from '../actions/addItem'
import getItems from '../actions/getItems'
class App extends Component {
constructor(props) {
super(props)
this.handleClick = this.handleClick.bind(this)
this.state = {text: ''}
}
handleClick(e){
console.log(e);
const {dispatch} = this.props
dispatch(addItem(e));
}
componentDidMount(){
console.log("COMPONENT MOUNT");
const {dispatch} = this.props
// dispatch(getItems())
}
componentWillReceiveProps(nextProps) {
console.log("GETTT IT");
console.log(nextProps)
}
render() {
return (
<div>
< h1 > Hallo </h1>
<AddTodo handleAddItem={this.handleClick}/>
<TodoList/>
</div>
)
}
}
App.propTypes = {
dispatch: PropTypes.func.isRequired
}
function mapStateToProps(state){
return {
AddTodo
}
}
export default connect (mapStateToProps)(App)
I hope this issue is not to basic and someone can help me. Thanks in advance!
If you inspect your redux state you will see that the following code sets up 2 more keys in the state (addItem
and getItem
):
const rootReducer = combineReducers({
addItem,
getItem
})
So, now to connect todos
you need to one of the 2 new keys. If todos
is not defined on those, then you need to add the reducer of todos
to the combineReducers
call.
So this needs to map to a valid location in state:
const mapStateToProp = state => ({todos: state})
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