Populate in mongoose

query

var mongoose = require('mongoose');
var Event = mongoose.model('Event');
var Calendar = mongoose.model('Calendar'); 

function eventController(app) {

  app.get('/calendar/:calendarid', function (req, res) {
		    Calendar
		    .findOne({ _id:req.params.calendarid })
		    .populate('events')
		    .exec(function (err, data) {
		    	console.log("executing populate");
		      if (err) {
		        return res.json({error:err})
		      }
		      return res.json(data)
		    })
		});	

exports.boot = eventController;	  

schemas

// Calendar model/schema in one file

exports.boot = function(mongoose) {
  var Schema = mongoose.Schema;
  var ObjectId = Schema.ObjectId;
  
  var Calendar = new Schema({
    creator : { type: Schema.ObjectId, ref: 'User'},
    name : { type: String, index:true },
    description : String,
    events : [{ type: Schema.ObjectId, ref: 'Event'}],
    group: [{ type: Schema.ObjectId, ref: 'Group'}],
    date : { type : Date, default:Date.now }
  });

  mongoose.model('Calendar', Calendar);
  
}

// And in another file the event model/schema

exports.boot = function(mongoose) {
  var Schema = mongoose.Schema;
  var ObjectId = Schema.ObjectId;

  var Event= new Schema({
    creator : { type: Schema.ObjectId, ref: 'User'},
    name : { type: String, index:true },
    description : String,
    attendees : [{ type: Schema.ObjectId, ref: 'User'}],
    calendar : { type: Schema.ObjectId, ref: 'Calendar'},
    date : { type: Date, default: Date.now}
  });

 
  mongoose.model('Event', Event);
}

weirdpopulateissue.js

var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var assert = require('assert')

console.log('\n===========');
console.log('    mongoose version: %s', mongoose.version);
console.log('========\n\n');

mongoose.connect('localhost', 'testing_weirdpopulateissue');
mongoose.connection.on('error', function () {
  console.error('connection error', arguments);
});


var Cal = new Schema({
  creator : { type: Schema.ObjectId, ref: 'User'},
  name : { type: String, index:true },
  description : String,
  events : [{ type: Schema.ObjectId, ref: 'Event'}],
  group: [{ type: Schema.ObjectId, ref: 'Group'}],
  date : { type : Date, default:Date.now }
});
var Calendar = mongoose.model('Calendar', Cal);

var Evt= new Schema({
  creator : { type: Schema.ObjectId, ref: 'User'},
  name : { type: String, index:true },
  description : String,
  attendees : [{ type: Schema.ObjectId, ref: 'User'}],
  calendar : { type: Schema.ObjectId, ref: 'Calendar'},
  date : { type: Date, default: Date.now}
});
var Event = mongoose.model('Event', Evt);

mongoose.connection.on('open', function () {
  var e = new Event({ name: 'weirdpopulateissue' });

  e.save(function (err) {
    if (err) return done(err);

    var cal = new Calendar({ events: [e], name: 'my cal' });
    cal.save(function (err) {
      if (err) return done(err);

      Calendar
      .findOne({ _id: cal._id })
      .populate('events')
      .exec(function (err, data) {
        if (err) return done(err);
        console.error('found', data);
        done();
      });
    })

  })
});

function done (err) {
  if (err) console.error(err.stack);
  mongoose.connection.db.dropDatabase(function () {
    mongoose.connection.close();
  });
}