Question

I have the following object relations between my three models (I am not using Backbone-relational… this is just describing the underlying structure of my data) :

Person has many Cars
Car has many Appraisals.

I have a single method to retrieve a Person, which brings along all the Cars and the Appraisals of those Cars. It looks like this:

{id: 1,
 name: John Doe,
 cars: [
        {id: 3, make: 'Porsche',
         appraisals: [
                        {id: 27, amount: '45000', date: '01/01/2011'}
                     ]
        },

        {id: 4, make: 'Buick', appraisals: []}
  ]
}

When I create a new Person I pass in this entire mess. In my Person’s initialize function I do this:

...
initialize: function() {
  //Cars => Collection of Car
  this.cars = new Cars();
  _.each(this.get('cars'), function(car) {
    this.cars.add(new Car(car));
  });
  this.unset('cars');
}
...

And in my Car initialize function I do something similar:

...
initialize: function() {
  //Appraisals => Collection of Appraisal
  this.appraisals = new Appraisals();
  _.each(this.get('appraisals'), function(appraisal) {
    this.appraisals.add(new Appraisal(appraisal));
  });
  this.unset('appraisals');
}
...

I also have to override the toJSON function for Person and Car models.

Is there anything wrong with this? I’ve seen it suggested elsewhere to make nested collections properties rather than attributes, and my experience confirms that is easier, but I’m wondering if I am breaking some rules or doing something dumb here.

Answer 1

I answered a similar question here: backbone.js – getting extra data along with the request

In the answer that I provided, it was more about a collection owning a model association — a has one, basically.

I think a Person should have a CarsList containing Car models. A Car should have an AppraisalsList containing Appraisal models. You would probably override the parse and toJSON functions of Person and Car as needed.

I would definitely avoid using attributes for associations. The unset functions in the above examples are a bad smell to me.