NodeJS: How to improve error handling when writing a model class for OrientDB

Question

I am building a little Node app and since I want to use OrientDB I cannot use Mongoose or the like for handling my data / models. So I have to come up with something on my own and I find it quite hard since I'm not that well vetted in Node.js (yet).

I am using oriento as my driver for OrientDB. Oriento's API is based on bluebird promises.

This is how far I got. But I am pretty sure there must be a better way to handle errors (like 'record not found').

Any hints on how to improve this are welcome. Maybe there even is a package for creating models that aren't tied to a specific database that I haven't found yet.

./utils/oriento.js

// instantiate it once and share in multiple places(models), since it offers 
// connection pooling
// Connect to Database
var Oriento = require('oriento');

var orientserver = Oriento({
  host: 'localhost',
  port: 2424,
  username: 'root',
  password: 'password'
});

var db = orientserver.use({
  name: 'database',
  username: 'root',
  password: 'password'
});

console.log('Using database: ' + db.name);

module.exports = db;

./models/user.js

var db = require('../utils/oriento.js');

var User = function (data) {  
  this.data = {
    username: data.username,
    email: data.email
  };
}

User.prototype.data = {}

User.findByUsername = function(username, callback){
  db.select().from('users').where({username: username}).one()
  .then(function (user) {
    if (user === undefined) {
        return callback(false);
    } else {
        callback(new User(user));
    }
  });
}

// add getters, setters, find etc...
module.exports = User;

./app.js

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');

var routes = require('./routes/index');
var users = require('./routes/users');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');

// Models
// I KNOW this doesn't belong here. 
// I just put it here for quick testing before writing any controllers

User = require("./models/user.js");
User.findByUsername('ole', function (user) {  
  if(user) {
    console.log("my object: ", user);
  } else {
    console.log("Nothing found");
  }
});

// etc...