nodejs authentication user-mysql model

user-mysql.js

// app/models/user-mysql.js
// -----------------------------------------------------------------------
// Original script from RisingStack nodehero-authentication tutorial
// https://blog.risingstack.com/node-hero-node-js-authentication-passport-js/
// Mysql conversion by manjeshpv
// https://gist.github.com/manjeshpv/84446e6aa5b3689e8b84
// My version minimizes changes needed to the original passport.js file
// Revision Date: 1/4/17
// -----------------------------------------------------------------------

// Database connection
var mysql       = require('mysql')
var connection  = mysql.createConnection({
				  host     : '127.0.0.1',
				  user     : 'root',
				  password : '',
          database : 'nodejs',
				})
const table  = 'passport_users'
// Encryption        
var bcrypt   = require('bcrypt-nodejs')

// Password functions
exports.generateHash = function(password) {
  return bcrypt.hashSync(password, bcrypt.genSaltSync(8), null)
}
exports.validPassword = function(password, userPassword) {
  return bcrypt.compareSync(password, userPassword)
}
// Query functions mimics mongoose findById and findOne
// return callback(err, user) to be used by done()
exports.findById = function(id, callback){  
  connection.query("SELECT * from " + table + " where id = ?", [id], function(err,rows){
    if(err)
        return callback(err, null)	
	  return callback(null, rows[0])
	})   
}
exports.findOne = function(field, value, callback){
  connection.query("SELECT * from " + table + " where ?? = ?",[field, value], function(err,rows){
  if(err){
    return callback(err, null)
  }
  if(rows.length > 0){    
    return callback(null, rows[0])
  }
  return callback(null, null)
  })
}
// Mimics mongoose save 
exports.save = function(obj, callback){
  var insertQuery = "INSERT INTO " + table + " ( email, password ) values (?,?)"
  connection.query(insertQuery, [obj.email, obj.password], function(err,rows){
    obj.id = rows.insertId
    return callback(null, obj)
  })	
}