Question

This is a general question about backbone.js and javascript, I’m intermediate in javascript:

If you have a collection of models, each connected to an instance of a view, is each model instance’s view instance containing a full instance of the view’s render method? If so, what is recommended way to ensure that the render method is ‘static’, so that memory is not wasted if each model instance requires the exact same render function?

In the example below, does each hat instance also contain an instance of the render function, or is it pointing to a ‘static’ render function?

    var Hat = Backbone.Model.extend({});

    var HatCollection = Backbone.Collection.extend({

        model : Hat,        

    });

    var HatView = Backbone.View.extend({

        render : function() {

            // output the hat's html

        }

    });

    var hats = new HatCollection([ new Hat(), new Hat(), new Hat()])

    hats.each(function(hat) {

        hat.view = new HatView({ model : hat });

    });

Answer 1

Just check if the render method is a member of the instance or the prototype:

(function () {

    var HatView = Backbone.View.extend({
        render : function() {
            console.log("rendering a hat...");
        }
    });

    var hview = new HatView();

    console.log(hview.hasOwnProperty("render")); // false

    console.log(hview.render === HatView.prototype.render); // true

}());