Redux state is undefined in mapStateToProps
You reducer doesn't have a default action in switch statement. Which is why even though you mentioned the initial state in reducer params, undefined is returned as store initial state
import React from 'react';import {Map,fromJS} from 'immutable';const reducer = (state = Map() ,action) => { switch(action.type){ case 'SET_STATE': return state.merge(action.state); default: return state; }}export default reducer;Adding the default statement will fix the issue :)
I ended up here too because I had failed to pass my rootreducer function to my createStore method. I had:
const store = createStore(applyMiddleware(...middlewares));I needed:
const store = createStore(rootReducer(), applyMiddleware(...middlewares));