Redux store does not have a valid reducer

Question

Haven't been able to find anything around here regarding this error:

"Store does not have a valid reducer. Make sure the argument passed to combineReducers is an object whose values are reducers."

My reducer

export default function FriendListReducer(state = {friends : []}, action) {   switch (action.type) {     case 'ADD_FRIEND':       return [         { friends : action.payload.friend }, ...state.friends       ]          default:       return state;   }   return state; } 

Combiner

import { combineReducers } from 'redux'; import { FriendListReducer } from './FriendListReducer';  const rootReducer = combineReducers({   friends: FriendListReducer }); export default rootReducer; 

My store config

import { applyMiddleware, createStore } from 'redux'; import thunkMiddleware from 'redux-thunk'; import createLogger from 'redux-logger'; import rootReducer from '../reducers/reducers';  export default function configureStore(initialState = { friends: [] }) {   const logger = createLogger({     collapsed: true,     predicate: () =>     process.env.NODE_ENV === `development`, // eslint-disable-line no-unused-vars   });    const middleware = applyMiddleware(thunkMiddleware, logger);    const store = middleware(createStore)(rootReducer, initialState);    if (module.hot) {     // Enable Webpack hot module replacement for reducers     module.hot.accept('../reducers/reducers', () => {       const nextRootReducer = require('../reducers/reducers').default;       store.replaceReducer(nextRootReducer);     });   }    return store; } 

Answer 1

Your import statement is incorrect. Either you use import { Foo } from 'bar' together with export Foo, or use import Foo from 'bar' if you export with export default Foo.

In other words, change either export default function FriendListReducer to export function FriendListReducer, or change the import statement from import { FriendListReducer } to import FriendListReducer.

Answer 2

If the object is empty.

 export  default  combineReducers({   }) 

This error will show.