populating nested subdocuments

populate_nested_docs.js

// mongoose v3.6.18
//
var mongoose = require('mongoose');
mongoose.connect('localhost/mydb');

var Schema = mongoose.Schema;

var MasterSchema = new Schema({
  name: String,
});

var PanelSchema = new Schema({
  name: String,
  master: [{type: Schema.Types.ObjectId, ref: 'Master'}]
});

var AppSchema = new Schema({
  name: String,
  panel: [{type: Schema.Types.ObjectId, ref: 'Panel'}]
});

var App = mongoose.model('App', AppSchema);
var Panel = mongoose.model('Panel', PanelSchema);
var Master = mongoose.model('Master', MasterSchema);

var master = new Master({name:'meester'});
master.save(function(err) {
  var panel = new Panel({name:'paneel'});
  panel.master.push(master);
  panel.save(function(err) {
    var app = new App({name:'application'});
    app.panel.push(panel);
    app.save(function(err) {
      if (err) throw new Error('not found');
      App.find({}).populate('panel').populate('master').exec(function(err, prog) {
        if (err) throw new Error('not found');
        console.log('%j',prog);
        process.exit();
      });
    });
  });
});

pupolate_with_multiple_populate_calls.js

var mongoose = require('mongoose');
mongoose.connect('localhost/mydb');

var Schema = mongoose.Schema;

var MasterSchema = new Schema({
  name: String,
});

var PanelSchema = new Schema({
  name: String,
  master: [{type: Schema.Types.ObjectId, ref: 'Master'}]
});

var AppSchema = new Schema({
  name: String,
  panel: [{type: Schema.Types.ObjectId, ref: 'Panel'}]
});

var App = mongoose.model('App', AppSchema);
var Panel = mongoose.model('Panel', PanelSchema);
var Master = mongoose.model('Master', MasterSchema);

var master = new Master({name:'meester'});
master.save(function(err) {
  var panel = new Panel({name:'paneel'});
  panel.master.push(master);
  panel.save(function(err) {
    var app = new App({name:'application'});
    app.panel.push(panel);
    app.save(function(err) {
      if (err) throw new Error('not found');
      App.find().populate({ path: 'panel' }).exec(function(err, second) {
        Panel.populate(second,{path:'master'}, function(err, res) {
          if (err) throw new Error('not found');
          console.log('%j', res);
          process.exit();
        });
      });
    });
  });
});