Can I link an external javascript file to an AngularJS controller?

Question

This may be a dumb question. I know AngularJS controllers use javascript code to keep the application logic outside of the view. But I was wondering if I could link an external javascript file to a controller so it didn't have to be so long.

If it is possible would you also share the syntax of how I would do this. Something like:

app.controller('demoCtrl', ['$scope', function ($scope) {
    $scope.msgtxt='Hello World';
    src=somejavascriptfile.js;
}]);

Answer 1

If your issue is that the controller logic is too long, you are correct that it is a code smell. You want to make the controller as thin as possible, just enough logic to handle the view events and updating the model (scope). If you want to refactor your controller code, the first step is to extract out the logic into service(s) (in angular lingo providers / factories / services). The services can then be injected into your controller, similar to how you have injected the $scope service.

Read this sitepoint article for details on how to do this.

The next step might be look for logic (mainly UI related) which can extracted into directives.

In case you need to use an external javascript library within your angular application, the optimal way is to add that script to the scripts section of your html file, and wrap the functionality in a service or a directive (if it is UI related). Make sure to check if there are angular modules available out there for the 3rd party library you want to pull in.