Bookshelf js model causes save/changed loop

Question

The following Bookshelf model hashes the users password when the model is saved, the only problem is that if I change that model.set() call to a model.save() it goes into an infinite save/changed loop.

var User = bookshelf.Model.extend({
    tableName: 'users',
    hasTimestamps: true,

    constructor: function() {
        var self = this;
        bookshelf.Model.apply(this, arguments);

        this.on('saving', function(model) {
            if(!model.get('password')) {
                return self.hashPassword(model);
            }
        });
    },

    hashPassword: function(model) {
        bcrypt.genSalt(10, function(error, salt) {
            bcrypt.hash(model.attributes.password, salt, function(error, hash) {
                model.set({password: hash});
                console.log(model.attributes);
            });
        });
    }
});

I know that Backbone has a silent: true option you can pass so that save() doesn't trigger a changed event but I don't think Bookshelf supports it.

How can I save the changes model.set() has made without causing a save/changed loop?

Answer 1

So it turns out that the model is saving before the hash_password method has returned a value, so I promiseified the bcrypt code like so:

hashPassword: function(password) {
    return new Promise(function(resolve, reject) {
        bcrypt.genSalt(10, function(error, salt) {
            if(error) return reject(error);

            bcrypt.hash(password, salt, function(error, hash) {
                if(error) return reject(error);
                return resolve(hash);
            });
        });
    });
}

and completely refactored the model's constructor to use it:

constructor: function() {
    var self = this;
    bookshelf.Model.apply(this, arguments);

    this.on('saving', function(model) {
        if(!model.attributes.password) {
            delete model.attributes.password;
        } else {
            return self.hashPassword(model.attributes.password)
            .then(function(hash) {
                model.set({ password: hash });
            });
        }
    });
}

Hope this helps somebody :-)