Subscriptions

Subscriptions are fields which use a different paradigm to resolve compared to the queries. Instead of getting a one time result, the subscription will ask the server to subscribe to real-time data (like streaming), and the client will receive data as soon as new data is made available by the subscription resolver.

Subscriptions are methods of a Resolver class decorated with @Subscription().

Options

The @Subscription() decorator supports parameters defined by the ISubscriptionOptions interface.

Example usage

import { Resolver, Subscription } from '@pequehq/graphql';
import { PubSubService } from '../your/services';
import { User } from '../your/dto'

@Resolver()
class ExampleResolver {
  constructor(private pubSub: PubSubService) {}

  @Subscription()
  userInserted(): User {
    return this.pubSub.asyncIterator('userInserted');
  }
}

Pub Sub

The PubSub pattern is well explained in Apollo documentation.

Please note that the basic PubSub implementation provided by the lib graphql-subscriptions is not suitable for production environments because it only supports a single server (in-memory), and it should be replaced by one of the available PubSub subclasses. Read more here.