Question

I want to be able to sort my models in a collection first by their required flag and then value alphabetically.

Currently my code looks like to this:

var myModel = Backbone.Model.extend({
    defaults: {
        required: true,
        value: '',
        ...
    }
};

var myCollection = Backbone.Collection.extend({
    model: myModel,
    comparator: function (model) {
        return -model.get('required');
    }
});

myCollection.create([
     {value: 'A', required: false},
     {value: 'B', required: true},
     {value: 'C', required: false},
     {value: 'D', required: false},
     {value: 'E', required: true}
]);

The comparator sorts my models by required first but I’m at a loss as to how to also sort them alphabetically. Currently when the view renders them they come out

E, B, D, C, A

I want them to be rendered:

B, E, A, C, D

Answer 1

Your “comparator” can return a string consisting of the value and a stringified version of your boolean “required” property that’ll order things the way you want:

comparator: function(model) {
  return (model.required ? "0" : "1") + model.value;
}

That way, value “A” is compared as “0A” or “1A” depending on the “required” flag.