Question

I have created a new backbone.js widget model which I hope to extend:

        var Widget = Backbone.Model.extend({
            constructor: function() {
              console.log('Widget constructor called.');
            }
        });

Depending on the page a user views a number of widgets will be loaded via Ajax, so for each widget I will do something like this:

        $.getScript('widgets/widget1', function(xhr){
            var widget1 = new pieChartWidget();
            widget1.render();
            widget1.update();
        });

Contents of “widgets/widget1”:

$(function() {

    var pieChartWidget = Widget.extend({
            render: function(json) {
              console.log('Widget render called.'); 
            },
            update: function(json) {
              console.log('Widget update called.'); 
            }
    });

});

In my Firebug console I get “pieChartWidget is not defined”. I know the Javascript is being loaded successfully, I just cannot extend the “Widget” model from it.

Answer 1

Your widget is defined within a function. So all variable declared there are only visible withing then functions scope.

$(function() {

  var pieChartWidget;

  // pieChartWidget is only visible here!

});

// pieChartWidget not visible here!

To have access to the widget from outside of the function you have to assign it to a global variable (eg. your applications namespace). You could also use window (not the preferred way).

Your code should work unchanged if you assign your widget to window like so:

$(function() {

  window.pieChartWidget = Widget.extend({
        render: function(json) {
          console.log('Widget render called.'); 
        },
        update: function(json) {
          console.log('Widget update called.'); 
        }
});

});