embeddedVirtuals.js

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

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

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

var sessionSchema = new Schema({ from: { type: Date, required: true }});
sessionSchema.virtual('startTime').get(function () {
  return 'start time was ' + this.from
});

var schema = new Schema({
    name: String
  , sessions: [sessionSchema]
});
var A = mongoose.model('A', schema);

mongoose.connection.on('open', function () {
  var a = new A({ name: 'embeddedVirtuals' });
  a.sessions.push({ from: new Date });

  console.log('a is ', a);
  console.log();

  a.save(function (err, a) {
    if (err) return done(err);

    A.findById(a, function (err, doc) {
      console.log('retreived ', doc);
      console.log();
      console.log('startTime: ', doc.sessions[0].startTime);
      done(err);
    });
  })
});

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