users_in_collaborations_publication.js

// publish users that are in the specified collaborations
Meteor.publish("usersInCollaborations", function (collaborations) {
  // grab the associated collaborators (personal and otherwise) for all collaborations
  let combinedCollabs = _.reduce(collaborations, (memo, name) => {
    // grab the collaboration
    let collab = Collaborations.findOne({ name });
    
    // get the collaborators and add them to the working list
    memo.concat(concat.getAssociatedCollaborators());
    
    return memo;
  }, []);
  
  return Meteor.users.find({
    "collaborations.personal": { $in: combinedCollabs }
  }, {
    fields: {
      "profile.name": 1
    }
  }
});