main.js

import React, { Component } from 'react';
import CheckoutContainer from './containers/CheckoutContainer';
import { createStore, applyMiddleware, combineReducers } from 'redux';
import thunk from 'redux-thunk';
import { Provider } from 'react-redux';
import * as reducers from './reducers';
import { pouchMiddleware, getState } from './redux-pouchdb';

getState().then(initialState =>{
  const createStoreWithMiddleware = applyMiddleware(thunk, pouchMiddleware)(createStore);
  const reducer = combineReducers(reducers);
  const store = createStoreWithMiddleware(reducer, initialState);

  const element = (
    <Provider store={store}>
      {() => <CheckoutContainer />}
    </Provider>);

  React.render(element, document.body);
});

redux-pouchdb.js

import PouchDB from 'pouchdb';

var db = new PouchDB('app');
const docId = 'redux-store';
const emptyDoc = {_id: docId};

export const getState = () => {
  return db.get(docId).catch(error => {
    return db.put(emptyDoc).then(() => emptyDoc);
  });
}

export const pouchMiddleware = ({ dispatch, getState }) => {
  return next => action => {
  	const ret = next(action);

  	db.get(docId).then(doc => {
  	  db.put({
  	    ...doc,
  	    ...getState()
  	  }).catch(error => {
  	    console.error(error);
      });
  	});
  	
  	return ret;
  }
};