Vulcan/packages/nova-subscribe/lib/custom_fields.js

import PublicationUtils from 'meteor/utilities:smart-publications'
import Posts from "meteor/nova:posts"
import Users from "meteor/nova:users"

Users.addField({
  fieldName: 'telescope.subscribedItems',
  fieldSchema: {
    type: Object,
    optional: true,
    blackbox: true,
    autoform: {
      omit: true
    }
  }
});

Posts.addField([
  {
    fieldName: 'subscribers',
    fieldSchema: {
      type: [String],
      optional: true,
      autoform: {
        omit: true
      },
      publish: true,
      join: {
        joinAs: "subscribersArray",
        collection: () => Users
      }
    }
  },
  {
    fieldName: 'subscriberCount',
    fieldSchema: {
      type: Number,
      optional: true,
      autoform: {
        omit: true
      }
    }
  }
]);

PublicationUtils.addToFields(Users.publishedFields.list, ["telescope.subscribedItems"]);
PublicationUtils.addToFields(Posts.publishedFields.list, ["subscribers", "subscriberCount"]);