How to trigger event on arbitrary function call using jQuery

Question

I'm wondering if it's possible to use jQuery's bind() to fire a custom event when an arbitrary function is called. Something like,

/* when cmsPlugin.func() is called, fire myCustom.func() too */
$.bind( cmsPlugin.func, myCustom.func );

We're using the Lightbox2 plugin for Drupal on a site.

When the lightbox is displayed, I want to fire some custom code which will attach to clicks on a "download" link in the Lightbox.

The Lightbox2 plugin doesn't appear to call $.trigger(), so I have a few options -

• Find a way to bind to javascript function calls. (In this case, Lightbox.end I believe.)
• Use an existing event, eg $(document).ready, which may (?) be fired as part of the lightbox display.
• Extend the existing function to add a $.trigger() call.
• Just hammer myCustom.func() repeatedly for a time after detecting that a lightbox-triggering element has been clicked. (Ewww.)
• ________ ?

---

Solution

I attempted to simplify my question by using the cmsPlugin.func / myPlugin.func but I think I might have confused myself in doing so. However, I hope that the solutions posted will be generic enough for future readers to use themselves.

Thanks Adam and Lucho. I didn't have any luck with Lucho's suggestion, but I suspect that this was my own fault and not Lucho's :)

At first I tried Lucho's example code, modifying it to fire Drupal.zipcart.init() when Lightbox.updateNav was executed. This didn't work for me.

I decided on Lightbox.updateNav() to extend because it was a simple function called late in Lightbox2's display method.

My attempt at modifying Lucho's code looked like this, but didn't work -

// NOT THE RIGHT SOLUTION (for me)
Lightbox.updateNav = function(_dz, _lb) { return function() {
        _lb.updateNav();
        _dz.init();
    };
}(Drupal.zipcart, Lightbox);

Here's the code I ended up using based on Adam's answer, which allows Drupal's ZipCart and Lightbox2 modules to play nicely together, making links with class="zipcart" in the lightbox correctly add files to the download cart.

(function(){
  var _updateNav = Lightbox.updateNav;
  Lightbox.updateNav = function () {
    $(document).bind('lightbox.updateNav', function() {
      Drupal.zipcart.init();
    });
    $("#lightbox").trigger('lightbox.updateNav');
    _updateNav.apply(this, arguments);
  }
})();
$(document).bind('lightbox.updateNav', function () { Drupal.zipcart.init(); });

Answer 1

You cannot bind event listeners to a function. Events are bound and triggered from DOM nodes, so you need to know how to select the lightbox's markup. jQuery allows doing this now, but you still need a wrapper to trigger the event.

The cleanest way I can think of to accomplish this would be to wrap the Lightbox.updateNav function and fire a custom event.

(function(){
  var _updateNav = Lightbox.updateNav;

  Lightbox.updateNav = function () {
    $("#lightbox").trigger('lightbox.updateNav');
    _updateNav.apply(this, arguments);
  }
})();

#lightbox needs to point to the lightbox markup that you can bind event listeners to. I don't know enough about LightBox2's API to tell you how to do this exactly.

This is better than a simple wrapper function because you can wire up as many listeners as you like.

$("#lightbox").bind('lightbox.updateNav', function() {})

Since the lightbox markup is likely created and destroyed dynamically, you would be better off using delegate instead (provided you have access to jQuery 1.4.2). If you can identify where the markup is inserted, attach a delegate to the parent element:

$('#lightbox-parent').delegate('#lightbox', 'lightbox.updateNav', function() {})

This is much better performance than .live() so I would recommend doing it this way if you can.