1652.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');

var dbname = 'goosetest-1652';
mongoose.connect('localhost', dbname);
mongoose.connection.on('error', function () {
  console.error('connection error', arguments);
});


var AddressSchema = Schema({ street: String, city: String, zip: Number })

var schema = new Schema({
    name: String
  , addresses: { type: [AddressSchema], validate: validator }
});


function validator (array) {
  var bad = [];

  var ok = array.every(function (address) {
    if (!address.isModified()) return true;

    if (!address.city /*etc */) {
      bad.push(address);
      return false;
    }

    return true
  })

  if (!ok) {
    this.invalidate('addresses', 'missing value', bad)
  }

  return true;
}

var A = mongoose.model('A', schema);


mongoose.connection.on('open', function () {
  var a = new A({
      name: '1652'
    , addresses: [{ street: '5 What Street', city: 'Palo Alto' }]
  });

  a.save(function (err) {
    if (err) {
      console.log(err)
      return done();
    }

    A.findById(a, function (err, doc) {
      console.log('found', doc);

      doc.addresses[0].city = '';
      doc.save(function (err) {
        if (err) {
          console.log(err) // error!
          return done();
        }
        done();
      })
    })
  })
});

function done () {
  mongoose.connection.db.dropDatabase(function () {
    mongoose.connection.close();
  });
}