javascript - React-Redux-没有为键 “coins”提供reducer

不知道为什么会出现以下错误。

我只是在设置商店， Action 和 reducer ，我还没有在任何东西上调用dispatch。

预期的

应用正常运行，Redux状态未更新

结果



src/index.js

import React from 'react'
import ReactDOM from 'react-dom'

import { createStore, applyMiddleware, compose } from 'redux'
import { Provider } from 'react-redux'
import thunk from 'redux-thunk'
import reducer from './reducer'

import App from './App'
import css from './coinhover.scss'

const element = document.getElementById('coinhover');

const store = createStore(reducer, compose(
    applyMiddleware(thunk),
    window.__REDUX_DEVTOOLS_EXTENSION__ && window.__REDUX_DEVTOOLS_EXTENSION__()
));

ReactDOM.render(
    <Provider store={ store }>
        <App />
    </Provider>, element);

src/reducer/index.js

import { combineReducers } from 'redux'
import { coins } from './coins'

export default combineReducers({
    coins
});

src/reducer/actions/coins.js

import * as api from '../../services/api'
import { storage, addToPortfolio } from '../../services/coinFactory'

export const ADD_COIN = 'ADD_COIN'

export function getCoin(coin) {
    return dispatch => {
        api.getCoin(coin)
            .then((res_coin)  => addToPortfolio(res_coin))
            .then((portfolio) => dispatch(updatePortfolio(portfolio)));
    }
}

export function updatePortfolio(portfolio) {
    return {
        type: ADD_COIN,
        portfolio
    }
}

终于src/reducer/coins/index.js

import { ADD_COIN } from './actions'

const initialState = [];

export default (state = initialState, action) => {
    switch(action.type) {
        case ADD_COIN:
            return action.portfolio;
        default:
            return state;
    }
}

最佳答案

您的问题在于如何导入coins reducer:

import { coins } from './coins'

后者尝试获取从./coins中的文件返回的命名导出。

您没有使用任何命名的导出仅export default，因此只需要按以下方式导入文件:

import coins from './coins';

使用后者将导致coins然后将包含export default的值；这将是硬币减少器。