store.js

import { combineReducers, createStore, applyMiddleware } from 'redux';
import storage from 'redux-persist/lib/storage';
import { persistReducer, persistStore } from 'redux-persist';
import promise from 'redux-promise';

// Create the root reducer as you normally would.
const rootReducer = combineReducers({
  myPersistentData: dataReducer,
  someMorePresistentData: randomReducer,
});

/* 
Create the configuration object to be used for transforming our simple
root reducer into a property on persistent storage.
*/

const config = {
  key: '_myPersistentDataKey',
  storage,
};

// Make your reducer persistent with persistReducer()
const reducer = persistReducer(config, rootReducer);

const store = createStore(
  reducer,                      // Your persistent reducer
  {},                           // Initial store state
  applyMiddleware(promise),     // middleware(s)
);

// Convert your store to be persistent accross app sessions.
const persist = persistStore(store);

export default { store, persist };