Meteor.js: how to change the cursor (record) passed to the client?

Question

JavaScript

Let's say there is a subscription that returns one specific record (cursor). There is a "nextPlayer" field, where the id of the user who goes next is indicated. But it is necessary that the nextPlayer field on the client has a value of either 0 (if the current client is walking) or 1 (if another is walking). So that the user id is not transmitted to the client. With what help it can be implemented?
Server code:

Meteor.publish('current-game', function(){ 
 return Games.find({users: this.userId, finished: {$exists: false}}, {limit: 1})
})

Answer 1

Perhaps it is worth adding one more field to each document in Games, "a la" myTurn : 1
And in the publication, do this

Meteor.publish('current-game', function(){ 
  let options = {limit: 1, fields: {myTurn: 0}}
  const myTurn = Games.findOne({users: this.userId, nextPlayer: this.userId, finished: {$exists: false}}))
  if (myTurn){
    options.fields.myTurn=1
 }
 return Games.find({users: this.userId, finished: {$exists: false}}, {limit: 1})
})

And on the client, check the property myTurn