zeit/next.js/examples/with-apollo/lib/initClient.js -- changed to support subscriptions

initClient.js

import { ApolloClient, createNetworkInterface } from 'react-apollo'
import { SubscriptionClient, addGraphQLSubscriptions } from 'subscriptions-transport-ws'

const uri = 'http://localhost:4000/graphql'
const subscriptionsURI = 'ws://localhost:4000/'
let apolloClient = null

function _initClient (headers, initialState, subscriptionsInterface) {
  return new ApolloClient({
    initialState,
    ssrMode: !process.browser,
    dataIdFromObject: result => result.id || null,
    networkInterface: subscriptionsInterface || createNetworkInterface({ uri })
  })
}

export const initClient = (headers, initialState = {}) => {
  if (!process.browser) {
    // Server uses a standard ApolloClient instance
    return _initClient(headers, initialState)
  }
  if (!apolloClient) {
    // Client uses an ApolloClient that supports subscriptions
    apolloClient = _initClient(headers, initialState, addGraphQLSubscriptions(
      createNetworkInterface({ uri }),
      new SubscriptionClient(subscriptionsURI, { reconnect: true })
    ))
  }
  return apolloClient
}

How does this fit in with example in the repo?