I have created a service in angularJS that uses btford.socket-io module to interact with the server.
Since in the service I have implemented some API that I use inside angular at the moment, but for later extension of the application I also need to give access to these API outside angular scope.
So that in future one could just call the function without having the need to create controller and other stuff.
At the moment I did this for a controller
var myController = angular.element($('body')).scope().myController;
Typically not good practice. But sometimes its needed.
document.body is the element Your angular application is mounted to
Another thing you might consider is 'closing' external api with angular via a factory.
This is essentially what angular does for you. But instead of creating the reference inside angular first and having to extract it, you'd create it outside, and register it with DI as a factory or value.