poll.resolvers.js

import { PubSub } from 'apollo-server'
import { POLL_CREATED } from '../events';
import * as pollService from '../services/poll.service'

const pubsub = new PubSub()

export default {
  // ... queries and mutations

  subscriptions: {
    [POLL_CREATED]: {
      subscribe: () => pubsub.asyncIterator(POLL_CREATED),
    },
  },
}