Why require an area. $ Digest () after $ compile (element) (scope) in unit testing

Question

The following is a very general general scenario used for the test directive:

var element,scope; beforeEach(inject(function ($rootScope,$compile) { scope = $rootScope.$new() element = angular.element('<div my-directive></div>') $compile(element)(scope) scope.$digest(); //why? })) 

I understand that $compile(element) returns a function that takes the scope parameter and exposes it to the element directive. I also understand that scope.$digest() executes a digest cycle and starts a dirty check. With all that, my question is, why should you call scope.$digest after calling $compile so that everything works in this situation?

Answer 1

This is the general code for checking the directive. $Compile associates the template with the scope and performs the link function, and $digest / $apply updates the bindings for models that can be modified using link .
When you call $Compile inside an ng-click handler or in a controller function, all execution is done inside the $digest loop. Angular is built in such a way that dynamically added elements (when executing this loop) are executed in a single loop. That’s why you don’t actually notice the difference and don’t recognize the need to link ratings after compilation. However, in unit tests, this is different where you have to tell Angular to execute the $digest cycle manually. This often leads to problems when testing $q promises, for example.