AngularJS Developer Interview Question:

Tell me how $scope.$apply() works?

Submitted by: Muhammad

$scope.$apply re-evaluates all the declared ng-models and applies the change to any that have been altered (i.e. assigned to a new value)
Explanation: $scope.$apply() is one of the core angular functions that should never be used explicitly, it forces the angular engine to run on all the watched variables and all external variables and apply the changes on their values
Submitted by: Muhammad