toJSON/serialize with plugins.virtuals breaks omitNew option

[jgr3go]

If you have virtuals defined on the model, even when using omitNew, the virtuals are returned.

let Person = bookshelf.Model.extend({
  virtuals: {
    fullName: function() {
      return this.get('firstName') + ' ' + this.get('lastName');
    }
  }
});
let p = new Person({firstName: 'Jon', lastName: 'Smith'});
p.toJSON({omitNew: true}); // { fullName: 'Jon Smith' }

This becomes a problem when loading relations that could be null. This virtual turns into { fullName: 'undefined undefined' } for instance, when it should be returning null.

[Playrom]

Fix Merged!