终极版/反应。实现后，combineReducers无法获得app的状态 _reducer

亦余心之所善兮，虽九死其犹未悔。这篇文章主要讲述终极版/反应。实现后，combineReducers无法获得app的状态相关的知识，希望能为你提供帮助。
将两个reducers组合在一起（EditButton和TodoApp）后，我的应用程序每次都开始崩溃。在它之前，当我只使用一个减速机TodoApp时，我对reducers没有任何问题。但现在我无法弄清楚出了什么问题，因为每次我在map函数中得到component的错误。错误“TypeError：无法读取未定义的属性'map'”。
那么，我忘记了什么？另外，我无法在App的嵌套组件或容器中获取状态。这也很奇怪，但在App中我可以通过console.log（）来做到这一点。
/ * REDUCERS * /

import { combineReducers } from 'redux' import { ADD_TODO, EDIT_TODO, DELETE_TODO, FILTER_TODO_UP, FILTER_TODO_DOWN } from '../Variables/Variables'const initialState = { todos: [] }function EditButton(state, action) { if (typeof state === 'undefined') { return 'Edit'; }switch (action.type) { case EDIT_TODO: return state = "Edit" ? "Done" : "Edit" default: return state } }function TodoApp(state, action) { if (typeof state === 'undefined') { return initialState; }switch (action.type) { case ADD_TODO: return Object.assign({}, state, { todos: [ ...state.todos, { id: action.id, text: action.text, done: action.done } ] }); case EDIT_TODO: return Object.assign({}, state, { todos: [ ...state.todos, { id: action.id, text: action.text, done: action.done } ] }); case DELETE_TODO: return Object.assign({}, { todos: state.todos.filter(todos => todos.id !== parseInt(action.id)) }); case FILTER_TODO_UP: return Object.assign({}, { todos: [ ...state.todos.sort((a, b) => b.id - a.id) ] }); case FILTER_TODO_DOWN: return Object.assign({}, { todos: [ ...state.todos.sort((a, b) => a.id - b.id) ] }); default: return state; } }export default combineReducers({TodoApp, EditButton})

【终极版/反应。实现后，combineReducers无法获得app的状态】/ * APP * /

import React, { Fragment } from 'react'; import TodoFormAdd from '../Containers/TodoFormAdd'; import TodoListAdd from '../Containers/TodoListAdd'; import TodoFormFilterAdd from '../Containers/TodoFormFilterAdd'; class App extends React.Component { constructor(props) { super(props); }render() { return( < Fragment> // console.log(this.props.state.getState()) - work! < TodoFormAdd /> < TodoListAdd store={this.props.store} /> < TodoFormFilterAdd /> < /Fragment> ); } }export default App;

/* 容器 */

import { connect } from 'react-redux'; import TodoList from '../Components/TodoList/TodoList'; import { DeleteTodo } from '../Actions/AddTodo'// console.log(this.props.state.getState()) - does not work!const mapStateToProps = state => ({ todos: state.todos }); const mapDispatchToProps = dispatch => ({ todoFormDelete: todo => dispatch(DeleteTodo(todo)) }); export default connect( mapStateToProps, mapDispatchToProps)(TodoList)

/* 零件 */

import React from 'react'; import TodoIteam from '../TodoIteam/TodoIteam'class TodoList extends React.Component { handleDelete = (e) => { let target = e.target; let closestDelete = target.closest('span'); let closestEdit = target.closest('button'); if (closestDelete) { let index = closestDelete.parentNode.getAttribute('index'); this.props.todoFormDelete(index); } else { return } }render(props) { // console.log(this.props.state.getState()) - does not work!return ( < ul onClick={this.handleDelete}> {this.props.todos.map((iteam, index) => // this where I get an error < TodoIteam key={index} index={iteam.id} {...iteam} /> )} < /ul> ); } }export default TodoList;

答案正如您在combineReducers中使用ES6属性简写表示法：
combineReducers({TodoApp, EditButton})
这相当于写combineReducers({ TodoApp: TodoApp, EditButton: EditButton })
但在你的CONTAINER里面你正在访问state.todos没有任何名为todos来自州而不是它的TodoApp因此你得到你的.map()错误：