相关疑难解决方法(0)

我在redux createStore方法中设置了InitialState,并将InitialState作为第二个参数

我在浏览器中出错:

<code>Uncaught Error: Reducer "postsBySubreddit" returned undefined during initialization. If the state passed to the reducer is undefined, you must explicitly return the initial state. The initial state may not be undefined.</code>

代码在这里:

import { createStore, applyMiddleware } from 'redux'
import thunkMiddleware from 'redux-thunk'
import createLogger from 'redux-logger'
import rootReducer from '../reducers/reducers'
import Immutable from 'immutable'
const loggerMiddleware = createLogger()
//const initialState=0
function configureStore() {
    return createStore(
    rootReducer,
     {postsBySubreddit:{},selectedSubreddit:'reactjs'},
     applyMiddleware(
     thunkMiddleware,
    loggerMiddleware
  )
 )
}
  export default configureStore …

我相信我正在复制Todo教程几行,我收到此错误:

错误:Reducer"addReport"在初始化期间返回undefined.如果传递给reducer的状态未定义,则必须显式返回初始状态.初始状态可能不是未定义的.

这是我的addReport reducer:

const addReport = (state = [], action) =>
{
  console.log(state)
  switch (action.type) {
    case ADD_NEW_REPORT:
    return [...state,
      addReports(undefined, action)
    ]
    }
}

我添加了logging语句,可以验证它是否返回一个空数组.即使将状态设置为1也会产生相同的结果.我错过了什么？