Function is undefined, Bookshelf.js model function

Question

I am using Bookshelf.js to handle a user registration API end-point, designed with NodeJS and ExpressJS. But upon POSTing to the register url, I keep hitting an error at one of the User model functions.

Here is routes/index.js

var User = require(./models/User);
router.post('/register', function(req, res, next){
  if(!req.body.username || !req.body.password){
    return res.status(400).json({message: 'Please fill out all fields'});
  }
  try {
      var hash = User.createPassword(req.body.password);
      console.log(hash);
      new User({email: req.body.username, name: req.body.username, password: hash}).save().then(function(model) {
          return res.json({token: this.generateJWT()});
      });
  } catch (ex) {console.log(ex.stack);}
});

Here is models/Users.js

var jwt = require('jsonwebtoken');
var bcrypt = require('bcrypt');
var bookshelf = require('../config/bookshelf');

var User = bookshelf.Model.extend({
  tableName: 'users',
  constructor: function() {
    bookshelf.Model.apply(this, arguments);
    this.on('saving', function(model, attrs, options) {
      console.log(this.createPassword(model.attributes.password));
    });
  },
  createPassword: function(password) {
    bcrypt.genSalt(10, function (err, salt) {
      if(err) return next(err);
      bcrypt.hash(password, salt, function (err, hash) {
        if(err) return next(err);
        return hash;
      });
    });
  },
  validPassword: function(password, encryptedPass) {
    bcrypt.compare(password, user.encryptedPass, function (err, match) {
      if(err) cb(err);
      return (match) ? true : false;
    });
  },
  generateJWT: function() {
    // set expiration to 60 days
    var today = new Date();
    var exp = new Date(today);
    exp.setDate(today.getDate() + 60);

    return jwt.sign({
      _id: this._id,
      email: this.email,
      exp: parseInt(exp.getTime() / 1000),
    }, 'SECRET');
  }
});

module.exports = User;

When I try to POST to register, I get the following stack trace:

TypeError: undefined is not a function
    at \routes\index.js:185:21
    at Layer.handle [as handle_request] (\node_modules\express\lib\router\layer.js:95:5)
    at next (\node_modules\express\lib\router\route.js:131:13)
    at Route.dispatch (\node_modules\express\lib\router\route.js:112:3)
    at Layer.handle [as handle_request] (\node_modules\express\lib\router\layer.js:95:5)

...

In the stack trace, \routes\index.js:185:21 is the following line: var hash = User.createPassword(req.body.password); at createPassword.

So what am I doing wrong here? Why is it failing to recognize the createPassword function?

Answer 1

User is a constructor but the method is defined on its prototype. You have to create an instance to call a method on. Try

      var user = new User({email: req.body.username, name: req.body.username, password: hash});
      var pwd = user.createPassword();
      user.save()

Note that from the look of your method, it's probably better as a static method (it doesn't access this), which the other answer describes how to create.

Answer 2

createPassword() is not defined as a static method (a.k.a. classProperties), but you are calling it as such. Try this model definition. It should expose createPassword() directly on the User class as a static method.

var User = bookshelf.Model.extend({ //instance methods
  tableName: 'users',
  constructor: function() {
    bookshelf.Model.apply(this, arguments);
    // ...
  },
  validPassword: function(password, encryptedPass) {
    // ...
  },
  generateJWT: function() {
    // ...
  }
}, { //static methods
  createPassword: function(password) {
    // ...
  }
});

Extra: You'll need to fix your createPassword, as it's async. Below I've converted it to a Promise-returning function (as bookshelf uses promises extensively) and show an example usage for your route handler

createPassword: function () {
    return new Promise(function (resolve, reject) {
        bcrypt.genSalt(10, function (err, salt) {
            if (err) return reject(err);
            bcrypt.hash(password, salt, function (err, hash) {
                if (err) return reject(err);
                resolve(hash);
            });
        });
    });
}

// in route handler

if (!req.body.username || !req.body.password) {
    return res.status(400).json({
        message: 'Please fill out all fields'
    });
}
try {
    User.createPassword(req.body.password)
    .then(function(hash) {

        console.log(hash);

        return new User({
            email: req.body.username,
            name: req.body.username,
            password: hash
        }).save();

    }).then(function (model) {

        return res.json({
            token: this.generateJWT()
        });

    }).catch(function(ex) {
        console.log(ex.stack);
    });
} catch (ex) {
    console.log(ex.stack);
}