configureStore.dev.js

import { createStore, applyMiddleware, compose } from 'redux'
import createSagaMiddleware, { END } from 'redux-saga'
import rootReducer from '../reducers'
import logger from 'redux-logger'

export default function configureStore(initialState) {
  const sagaMiddleware = createSagaMiddleware()

  const enhancer = compose(
    applyMiddleware(sagaMiddleware, logger),
    window.__REDUX_DEVTOOLS_EXTENSION__ && window.__REDUX_DEVTOOLS_EXTENSION__()
  )

  const store = createStore(
    rootReducer,
    initialState,
    enhancer
  )

  if (module.hot) {
    // Enable Webpack hot module replacement for reducers
    module.hot.accept('../reducers', () => {
      const nextRootReducer = require('../reducers').default
      store.replaceReducer(nextRootReducer)
    })
  }

  store.runSaga = sagaMiddleware.run
  store.close = () => store.dispatch(END)
  return store
}