AngularJS register controller once - angularjs

Question

That's what I'm doing. There is application with pages and different controls that may be put on pages by site admin/editor. All pages share one ng-app defined on master page. All controls are supplied with .js files with angular controllers. Let's suppose that I have an image gallery block:
<div ng-controller='imageGalleryCtrl'>
do something amazing here
</div>
<script src='imageGallery.js'></script>
Inside script there is a simple controller registration like:
angular.module('myApp').controller('imageGalleryCtrl', ... );
So. If I have 10 image galleries, I'll execute controller registration 10 times. It looks like this will work, but hell - I don't want it to be so =)
For now I just have all controls' scripts registration on a master page, but I don't like it as well, because if there is no image gallery on a page, I don't want it's script be downloaded during page load.
The question is - is there any proper way to understand if controller have been registered in a module already and thus prevent it from re-registering?
---------------
Well, though I've found no perfect solution, I must admit that the whole idea isn't very good and I won't think about it before my site will grow too big to assemble whole angular app on master page.

Answer 1

You should declare your controller but once. Instead of having one controller per gallery, have your single controller handle all image galleries. The controller should make a request to the REST backend to fetch the images of the desired gallery.
I see that instead of ng-view, you're using the ng-controller directive, indicating that probably you're not using Angular's routing. Try switching to using routes.
Have a look at Angular.js routing tutorial. It shows you how to use the ngRoute module. Then, in the next chapter, the use of $routeParams is described. Via the $routeParams service, you can easily say which gallery should be displayed by providing its ID in the URL; only one controller will be necessary for all your galleries.
If you really must check whether a given controller has been declared, you can iterate through the already declared controllers (and services... and pretty much everything else) by checking the array angular.module("myApp")._invokeQueue. The code would probably look something like this (not tested!):
var isRegistered = function(controllerName)
{
var i, j, queue = angular.module("myApp")._invokeQueue;
for (i = 0, j = queue.length; i < j; ++i) {
if (
queue[i][0] === "$controllerProvider"
&& queue[i][1] === "register"
&& queue[i][2][0] === controllerName
) {
return true;
}
}
return false;
};
Bear in mind however that while this may (or may not) work, it's far from being the correct thing to do. It's touching Angular's internal data that's not meant to be used in your code.