为什么单个减速器会起作用，但是实现联合减速器会抛出错误？

问题描述

我正在尝试实施联合减速器，如果有人可以注意的话，我所看到的一切都是正确的。如果我将每个减速器都放进去，但是放进rootReducer，什么也没用。给我props.mutts / felines / applicants.map错误不是功能。

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import { createStore,applyMiddleware,compose} from 'redux';
import thunk from 'redux-thunk';
import { Provider } from 'react-redux';
import { combineReducers } from 'redux';
import  applicantReducer  from './reducers/applicantReducer';
import  catReducer  from './reducers/catReducer';
import  dogReducer  from './reducers/dogReducer';
import App from './App';

import * as serviceWorker from './serviceWorker';

const composeEnhancers = window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ || compose;

const rootReducer = combineReducers({
       applicants: applicantReducer,cats: catReducer,dogs: dogReducer
})

let store = createStore(rootReducer,composeEnhancers(applyMiddleware(thunk)))

ReactDOM.render(
  <React.StrictMode>
    <Provider store={store}>
      <App />
    </Provider>
  </React.StrictMode>,document.getElementById('root')
);

解决方法

函数 map 仅可用于数组，而不能用于对象。

如果您console.log（） props.mutts ，您会发现它是一个对象。

,

我需要在容器文件的mapStateToProps中添加reducer。

const mapStateToProps = (state) => {
    return{
        cats: state.catReducer.cats
    }
}