Proper way to publish with null fields?


I have a collection which has a possibility of null values. Let’s say it’s called Student. If a student does not have an advisor, the field Student.advisorId is null. If a user does not have a login, their Student.userId is null. Same with, for example, Student.profileImageId

This is giving me a problem with ugly publications

Meteor.publish('student', function (studentId) {
  return Students.find({ _id: patientId }).map(function(doc) {
    var cursors = [];
    if(!_.isNull(doc.profileImageId) {
      cursors.push(Thumbnails.find({ _id: doc.profileImageId }));
    if(!_.isNull(doc.advisorId) {
      cursors.push(Advisors.find({ _id: doc.advisorId }));
    // ... etc.
    return cursors;

What is a good way to handle this?