frontend/src/app/graphql.module.ts

import { NgModule } from '@angular/core';
import { APOLLO_OPTIONS } from 'apollo-angular';
import {
  ApolloClientOptions,
  ApolloLink,
  concat,
  InMemoryCache,
} from '@apollo/client/core';
import { HttpLink } from 'apollo-angular/http';
import { environment } from '../environments/environment';

const uri = environment.apiUrl + '/graphql'; // <-- add the URL of the GraphQL server here

const cleanTypeName = new ApolloLink((operation, forward) => {
  if (operation.variables) {
    const omitTypename = (key: string, value: any) =>
      key === '__typename' ? undefined : value;
    operation.variables = JSON.parse(
      JSON.stringify(operation.variables),
      omitTypename
    );
  }
  return forward(operation).map((data) => {
    return data;
  });
});

export function createApollo(httpLink: HttpLink): ApolloClientOptions<any> {
  return {
    link: concat(cleanTypeName, httpLink.create({ uri })),
    cache: new InMemoryCache({}),
  };
}

@NgModule({
  providers: [
    {
      provide: APOLLO_OPTIONS,
      useFactory: createApollo,
      deps: [HttpLink],
    },
  ],
})
export class GraphQLModule {}