javascript - React+Redux - Uncaught Error : Expected the reducer to be a function

Question

我尝试了简单的 react、redux、ajax 工作示例并遵循了 Reddit API tutorial ，但我无法创建商店并收到错误消息:

Uncaught Error: Expected the reducer to be a function.

index.jsx

...

import { createStore, applyMiddleware } from 'redux'
var thunkMiddleware = require('redux-thunk');
var createLogger = require('redux-logger');
var rootReducer = require('./reducers.js');

        const loggerMiddleware = createLogger();

        function configureStore(initialState) {
            return createStore(
                rootReducer,
                initialState,
                applyMiddleware(
                    thunkMiddleware,
                    loggerMiddleware
                )
            )
        }

        const store = configureStore();

...

rootReducer.js

import { combineReducers } from 'redux';

function products(state = {
    isFetching: false,
    didInvalidate: false,
    items: []
}, action) {
    switch (action.type) {
        case 'REQUEST_PRODUCTS':
            return Object.assign({}, state, {
                isFetching: true,
                didInvalidate: false
            })
        case 'RECEIVE_PRODUCTS':
            return Object.assign({}, state, {
                isFetching: false,
                didInvalidate: false,
                items: action.posts,
                lastUpdated: action.receivedAt
            })
        default:
            return state
    }
}

function specialPosts(state = { }, action) {
    switch (action.type) {
        case RECEIVE_SPECPOSTS:
        case REQUEST_SPECPOSTS:
            return Object.assign({}, state, {
                req: true
            })
        default:
            return state
    }
}

const rootReducer = combineReducers({
    products,
    specialPosts
});

export default rootReducer;

rootReducer 的类型是对象，但为什么呢？我应该将 createStore 函数更改为 rootReducer.default 吗？

return createStore(
    rootReducer.default,
    initialState,
    applyMiddleware(
        thunkMiddleware,
        loggerMiddleware
     )
)

package.json

"redux-logger": "^2.6.1",
"react-redux": "^4.4.1",
"react-redux-provide": "^5.2.3",
"redux": "^3.3.1",
"redux-thunk": "^2.0.1",

Answer 1

const rootReducer = combineReducers({
    products,
    specialPosts
});

const store = createStore( rootReducer, applyMiddleware( thunkMiddleware ));

然后根据各个 reducer 函数返回的初始状态自动创建初始状态。这些单独的状态可以作为 state.products 和 state.specialPosts

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