1048.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_1048');
mongoose.connection.on('error', function () {
  console.error('connection error', arguments);
});

var schema = new Schema({
    name: String
  , databases: { 0: { keys: Number, expires: Number }, 15: { keys: Number, expires: Number }}
  //, databases: Schema.Types.Mixed
});

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

mongoose.set('debug', true)
mongoose.connection.on('open', function () {
  var a = new A({ name: '1048', databases: { 0: { keys: 100, expires: 0}, 15: { keys: 1, expires: 0 } }});

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

    A.collection.find(function(err, cursor){
      cursor.toArray(function (err, result) {
        console.log('native', result[0]);

        A.find(function (err, docs) {
          console.error('mongoose', docs[0]);
          done(err);
        });
      });
    });
  })
});

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