overridden-apollo.js

import ApolloService from 'ember-apollo-client/services/apollo';
import { persistCache } from 'apollo-cache-persist';

class OverriddenApollo extends ApolloService {

  async init() {
    await persistCache({
      this.cache(),
      storage: window.localStorage,
    });
  
    super.init(...arguments);
  }
  
  cache() {
    if (!this._cache) {
      this._cache = new InMemoryCache();
    }

    return this._cache
  }
}