saveorder.js

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

console.error(
    '\n==========='
  , '    mongoose version: '
  , mongoose.version
  , '========\n\n'
);

var Schema = mongoose.Schema;
mongoose.connect('localhost', 'testing_saveorder');
mongoose.connection.on('error', function () {
  console.error(arguments);
});

var schema = new Schema({
    name: String
});
schema.pre('save', function (next) {
  console.error('pre save');
  next();
});
schema.post('save', function () {
  console.error('post save start');
  A.update({}, {name: 'b'}, function(err, numAffected) {
    if (err) {
      console.error(err);
      return;
    }
    console.error('post save end', numAffected);
    return;
  });
});

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

mongoose.connection.on('open', function () {
  var a = new A({ name: 'saveorder' });
  a.save(function (err, a) {
    console.error('save callback');
    mongoose.connection.db.dropDatabase(function () {
      mongoose.connection.close();
    });
  })
});