store.js

import { createStore, applyMiddleware } from 'redux';
import { composeWithDevTools } from 'redux-devtools-extension';
import thunk from 'redux-thunk';
import reducer from "../reducers";

const store = createStore(
    reducer,
    (localStorage['store']) ?
        JSON.parse(localStorage['store']) :
        {},
    composeWithDevTools(
        applyMiddleware (thunk)
    )
);

store.subscribe(()=> localStorage['store'] = JSON.stringify(store.getState()));

export default store;