Question

I have been going thru this book “developing backbone.js application”
where on page 18 theres a model function which goes like this:

    (function($){
    var Photo = Backbone.Model.extend({
        defaults: {
            'src': 'placeholder.jpg',
            'title':'an image placeholder',
            'coordinates':[0,0]
            },
        initialize:function(){
            this.on("change:sr", function(){
                var src = this.get("src");
                console.log("Image src has been updated to: "+src);
                });
            },
        changeSrc: function(source){
            this.set({'src':source});
            }
        });
    var somePhoto = new Photo({'src':'test.jpg', 'title':'testing'});
    somPhoto.changeSrc('thatPhoto.jpg');
    })(jQuery);

Its give me an error as

TypeError: this.on is not a function
this.on("change:src", function(){

on console.
Any Idea how i may solve this problem. I’m entirely new to Backbone.js.
Any Help is appreciated.

Answer 1

You might be using an old version of Backbone. on/off were only added on 0.9.0, before that they were called bind and unbind.

You should update to the latest Backbone (0.9.9 at the time of writing).