使用Immutable JS和Redux - 动作未定义

Question

I am using Redux and Immutable JS . I set up the store like this

import { combineReducers } from 'redux-immutable';

...
const rootReducer = combineReducers({});    
import { initialState } from '../reducers/...';

export const store = createStore(
    combineReducers(rootReducer, initialState),
    composeEnhancers(
        applyMiddleware(...middleware)
    )
);

Now I get the following error

// reducers/.../initialState.js

export function foo(state = initialState, action) {
    switch (action.type) {
     ...
...

TypeError: Cannot read property 'type' of undefined

and it highlights switch (action.type) { .

When I am not using redux-immutable and set up my store like this

import { ..., combineReducers } from 'redux';    

export const store = createStore(
    combineReducers({ initialState }),
    composeEnhancers(
        applyMiddleware(...middleware)
    )
);

I do not get an error. I do not understand why it says that action.type is undefined . Any ideas?

Answer 1

I think your code should look like this

export const store = createStore(
    rootReducer, initialState,
    composeEnhancers(
        applyMiddleware(...middleware)
    )
);
// I removed the combineReducers()

---

Reference: https://github.com/gajus/redux-immutable#usage

Example:

import {
  combineReducers
} from 'redux-immutable';

import {
  createStore
} from 'redux';

const initialState = Immutable.Map();
const rootReducer = combineReducers({});  // we use the combineReducers() here
const store = createStore(rootReducer, initialState); // and don't need to use it here

Answer 2

Your initialState should not be a Reducer. You should only combine all your Reducers.

Your initial State should be an object (State).

eg

{
 loaded: true,
 someDataString: ''
}

Answer 3

combineReducers only takes reducers:

const yourRootReducer = combineReducers({ someReducer, someOtherReducer })

It doesn't take initialState , your individual stores can (and createStore though you usually don't need to there).

Your call to createStore should be:

const store = createStore(
  rootReducer,
  initialState, // can be undefined
  composeEnhancers(
    applyMiddleware(...middleware)
  )
);

Assuming middleware is an array.