zombie killer: a backbone view mixin

destroyable.js

/**
* View mixin to properly cleanup dom, backbone, and custom event listeners.
* A view zombie killer.
* e.g. myView.destroy(); OR destroyable.destroy.call(myView);
*
* CAVEAT:
* Although custom events will stop triggering, custom event listeners 
* are not automatically removed since the binding context is unknown. e.g.
* otherView.on('foo', thisView.doSomething, thisView);
* 
* Custom event listeners should be removed in the same context where the 
* listener was attached, by listening to the 'destroy' event. e.g. 
* 
* thisView.on('destroy', function(){
*   otherView.off('foo', thisView.doSomething);
*   // or, for convenience
*   thisView.offOf(otherView);
* });
* // or as a cryptic one-liner:
* thisView.on('destroy', thisView.offOf.bind(thisView, otherView));
* 
**/
define([], function(){
	return {
		// removes event listeners from dom, model, and collection. 
		// also stops firing custom events.
		destroy: function(){
			var view = this;
			// remove model or collection bindings
			if(view.model) view.model.off(null, null, view);
			if(view.collection) view.collection.off(null, null, view);

			// trigger last event before destruction--so custom bindings can be removed.
			view.trigger('destroy', view); 
			// stop triggering custom events
			view.off();

			// remove event listeners (delegates to jQuery.empty() for view work)
			view.remove();
		},
		// removes event listeners from the provided object.
		// obj argument should be a backbone object that extends events.
		offOf: function(obj){
			obj.off(null, null, this);
		}
	};
});

don't need this garbage with backbone v.0.9.9's introduction of listenTo.