Question

I could use some help here, I can’t figure out why the populate method doesn’t work as expected.
I want to model some “rooms” with people inside them.

var PersonSchema = new Schema({
    _id   : Schema.ObjectId,
    name  : String,
});
var Person = mongoose.model('Person', PersonSchema, 'Person');

var RoomSchema = new Schema({
      _id    : Schema.ObjectId, 
      name : String,
      People : [{ type: Schema.ObjectId, ref: 'Person' }],
});
var Room = mongoose.model('Room', RoomSchema, 'Room');

So, I have a Person collection with one entry:

{ 
"name" : "person1", 
"_id" : ObjectId("4f9e5bb68bcd69fb0c000002") 
}

and a Room collection with one entry:

{ 
"_id" : ObjectId("4f9e5bb68bcd69fb0c000001"), 
"name" : "room1", 
"People" : [ ObjectId("4f9e5bb68bcd69fb0c000002") ] 
}

When I try to execute this query:

Room.findOne({ 'name': 'room1' }).populate('People').run(function (err, result) {
  if(err) console.log(err);
  console.log(result);
});

I get as output:

{ _id: 4f9e5bb68bcd69fb0c000001,
  name: 'room1',
  People: []
}

Why doesn’t Mongoose populate the people field? I just don’t understand what could be wrong.

Answer 1

This problem was a bug in 2.x version of mongoose. It has been fixed: https://github.com/LearnBoost/mongoose/issues/877