1408.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 = 'testing_1408';
console.log('dbname: %s', dbname);
mongoose.connect('localhost', dbname);
mongoose.connection.on('error', function () {
  console.error('connection error', arguments);
});

var PreferenceSchema = new Schema ({
    _id: {type: Schema.ObjectId, auto: true},
    preference: { type: String, required: true },
    value: { type: Schema.Types.Mixed }
}, { versionKey: false });

var BrandSchema = new Schema({
settings: {
    preferences: [PreferenceSchema],
}
});
var A = mongoose.model('A', BrandSchema);

mongoose.connection.on('open', function () {
  mongoose.set('debug', true)

  var a = new A({
    settings: {
      preferences:
       [ { preference: 'group_colors', value: false },
         { preference: 'can_force_orders', value: true },
         { preference: 'hide_from_buyers', value: true },
         { preference: 'no_orders', value: '' }
       ]
      }
  })

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

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

      var newData = {
        settings: { 
          preferences: 
           [ { preference: 'group_colors', value: true },
             { preference: 'can_force_orders', value: true },
             { preference: 'custom_csv', value: '' },
             { preference: 'hide_from_buyers', value: false },
             { preference: 'nozoom', value: false },
             { preference: 'no_orders', value: false }
          ]
        }
      }

      doc.set('settings', newData.settings, { merge: true });
      doc.save(function (err) {
        if (err) return done(err);

        A.findById(doc, function (err, doc) {
          if (err) return done(err);
          console.log('found settings after update', require('util').inspect(doc.settings, { depth: null }));
          done();
        })
      })
    });
  })
});

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