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';

// Update the GraphQL endpoint to any instance of GraphQL that you like
const GRAPHQL_URL = 'http://localhost:8000/graphql';

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

// Export a HOC from next-with-apollo
// Docs: https://www.npmjs.com/package/next-with-apollo
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 || {}),
    })
);