next.js/examples/with-redux-code-splitting/config/redux.js

import { createStore, applyMiddleware } from 'redux'
import { composeWithDevTools } from 'redux-devtools-extension'
import thunkMiddleware from 'redux-thunk'
import withRedux from 'next-redux-wrapper'
import { rootReducer } from 'fast-redux'

export const initStore = (initialState = {}) => {
  return createStore(rootReducer, initialState,
    composeWithDevTools(applyMiddleware(thunkMiddleware)))
}

export const reduxPage = (comp) => withRedux(initStore)(comp)