apollo-client.js

import { ApolloClient } from 'apollo-client'
import { InMemoryCache } from 'apollo-cache-inmemory'
import withApollo from 'next-with-apollo'
import { createHttpLink } from 'apollo-link-http'
import fetch from 'isomorphic-unfetch'

const GRAPHQL_URL = '/api/graphql'

const link = createHttpLink({
  fetch, // Switches between unfetch & node-fetch for client & server.
  uri: GRAPHQL_URL
})

export default withApollo(
  // You can get headers and ctx (context) from the callback params
  // e.g. ({ headers, ctx, initialState })
  ({ initialState }) =>
    new ApolloClient({
      link,
      cache: new InMemoryCache()
        //  rehydrate the cache using the initial data passed from the server:
        .restore(initialState || {})
    })
)