Question

I have a backbone model which contains an array which I am updating with a simple id (I didn’t want to add nested collection).

It seems fairly straightforward to me, but for some reason I’m getting an Uncaught TypeError: Object [object Object] has no method 'preshow' error.

I have a list of classes, and a form with the class being entered.
The user can click an item on the classlist to add it as a prerequisite to the class being edited. This triggers the ‘add_prerequisite’ in the ‘ClassInput’ view.

I’ve left out the code that I think is probably not needed.

Myapp.ClassInput = Backbone.Views.extend({
        initialize: function(){
         Myapp.class = this.model;
         Myapp.class.bind("add_prerequisite", this.add_prerequisite);
        },
        add_prerequisite: function(prerequisite){
         // this is a method in my model which adds the prerequisite id to this class
          class.add_prerequisite(prerequisite)

         //this is the line triggering the error
          this.show_pre(prerequisite);
         },

       show_pre: function(prerequisite){
          alert(prerequisite);
         }

});

Myapp.Classes.ClassList = Backbone.Views.extend({


     add_prerequisite: function(){
        Myapp.class.trigger('add_prerequisite',this.model.id);
     }
});

Answer 1

You need to bind the context of add_prerequisite to your backbone model.

To do that, you just have to add a third argument to the bind method

initialize: function() {
  Myapp.class = this.model;
  //bind the context of this.add_prerequisite to this
  Myapp.class.bind('add_prerequisite', this.add_prerequisite, this); 
}