Javascript Events vs. Callbacks In MVC Scenario

Question

I'm trying to work out a nice way to have views and controllers and minimize the ties between them.

Aside from multiple subscribers to one event, is there any major difference between js code like this:

var customers = {
    get: function(callback) {
        $.get('/customers', {}, function(data) { 
            callback.call(this, data); 
        });
    }
};

And an event-driven approach like this (event object is just pseudo code):

var customers = {
    get: function() {
        $j.get('/customers', {}, function(data) { 
            event.publish('customers.loaded', data); 
        });
    }
};

In both cases, the consumer of the customers object is ignorant of its inner workings. Does one way have an advantage over the other?

Answer 1

Event's are callbacks, but the difference is when and where they're bound. In the first case, you need to have a reference to the callback at the time that get is called, additionally it's limited to a single callback.

In the second scenario, (assuming you're triggering an event with that pseudo-code) you could have bound a callback outside of the scope of where get is called, allowing for stronger data-encapsulation. Additionally, events support triggering multiple callbacks, so that different functions can be executed depending on what has had access to the customers object.

I'd recommend going with the event-oriented solution as JavaScript is an event-oriented language.

Answer 2

The answer is quite straight forward : since an event may have unlimited event handlers(which are nothing but callbacks)... and a callback is just a single callback, I suggest that you go towards the event driven programming method.