Can I use AngularJS's $q outside an Angular component?

Question

I am writing a browser app, and I have a file that creates an object and initializes it. The app is written in AngularJS, but the file in question is plain Javascript, outside the Angular ecosystem.

I want to use promises in that file, but since Angular contains an an implementation of Q, I'd rather just use that than bring in another library.

I am also using RequireJS.

So, is there a way to use $q in a non-Angular file?

Ygerne

i don't see why not- just pass it at the appropriate time. – Avalokitesvara

Answer 1

You can do this by using the angular.injector() method which returns an $injector function that can be injected with dependencies that you need (e.g. $http, $q) through its invoke() method.

DEMO

Something like this:

angular.injector(['ng']).invoke(['$q', function($q) {

  $q.when('hello world').then(function(message) {
    window.alert(message);
  });

}]);

Note that the array passed to angular.injector() is a list of modules, I included the ng module because that is where the AngularJS core dependencies are located.

Cubism

But this way, $q will use a different $rootScope as the rest of the app. So using $rootScope.$apply() on the "normal" $rootScope (e.g. in unit tests) won't work for that $q, right? – Checkered

@Ignitor. That is not necessarily true, the ng module is technically added as a dependency for all modules. Therefore the $rootScope for the module that you create also shares the $rootScope of the ng module. As of the writing of this comment, the angular.js version is 1.5.8, you will see that the ng module is added as a default module for all modules in the bootstrap process, in this line. Additionally, the native angularjs services, providers, factories and values resides in this module. – Cubism

Just tried it: I saved a reference to the $rootScope within a controller and compared it to the $rootScope I've got from this: angular.injector(['ng']).invoke(['$rootScope', function($rootScope) { console.dir($rootScope); }]). They do not match and even have different $ids. – Checkered