different types of submodels pointing to the same Model

[LiorZ]

When using different keys (types) pointing to the same model , only one of the key ended up pointing to the actual model, the other is discarded, and as a result when using type "koko", we get the Mammal Model.

This bug can be avoided when using a different model class for Koko, I presume.

var Animal = Backbone.RelationalModel.extend();

var Mammal = Animal.extend({
    subModelTypes: {
        'primate': 'Primate',
        'carnivore': 'Carnivore',
        'koko':'Carnivore'
    }
});

var AnimalCollection = Backbone.Collection.extend({model:Animal});

window.Primate = Mammal.extend();
window.Carnivore = Mammal.extend();

var MammalCollection = AnimalCollection.extend({
    model: Mammal
});

// Create a collection that contains a 'Primate' and a 'Carnivore'.
var mammals = new MammalCollection([
    { id: 3, species: 'chimp', type: 'primate' },
    { id: 5, species: 'panther', type: 'carnivore' },
    {id: 33, species:'fat_dog', type:'koko' }
]);

var chimp = mammals.get( 3 );

var fat_dog = mammals.get(33);
alert('fat_dog is an animal? ' + ( fat_dog instanceof Animal ) + '\n' +
    'fat_dog is a carnivore? ' + ( fat_dog instanceof Carnivore ) + '\n' +
    'fat_dog is a primate? ' + ( fat_dog instanceof Primate ) );

alert( 'chimp is an animal? ' + ( chimp instanceof Animal ) + '\n' +
    'chimp is a carnivore? ' + ( chimp instanceof Carnivore ) + '\n' +
    'chimp is a primate? ' + ( chimp instanceof Primate ) );

[PaulUithol]

Just wondering, why would you have two keys point to the same model?

[LiorZ]

Taking from the above example, If I have a Dog and a Wolf, each should be represented by the Carnivore model but I might want to show them by using different views.

So basically, you might want to reuse the type attribute to assign a different view to a model.

Otherwise, you are forced to create a model (or a dummy model that inherits from the main one) for each such type.