src/bootstrap/generateStore.js

import { createStore, compose, applyMiddleware } from 'redux';
import thunk from 'redux-thunk';

import reducers from '../reducers';

const enhancer = () => compose(
  applyMiddleware(thunk),
  window.devToolsExtension ? window.devToolsExtension() : f => f,
);

/**
 * instantiate store
 * @type {Object}
 */
const initialState = {
  tellers: [],
};

export default mode => createStore(
  reducers,
  initialState,
  enhancer(mode),
);