I was writing some code and realized that angularjs1.5+ component doesn't actually receive the $scope.$broadcast event, means $scope.$on never run in component controller function.
Though I was able to $emit the event from the component controller and received by the parent controller by $on, but it just doesn't listen for the broadcast event.
broadcast from parent: $scope.$broadcast('parentEvnt', [1,2,3]);
but NOT recieved in component : $scope.$on('parentEvnt', function(event, data){ \\
I created this plunker to show the issue.
Searched some articles and as well on SO but didn't found any answer, and tried with $rootScope.$broadcast that didn't help too.
and, If it is not possible, then what's the best way to notify the component from any random place in app?
The problem here is you are broadcasting the event even before your child controllers initialize and start listening to those event. Hence, it doesn't matter whether you use $scope or $rootScope to broadcast :)
For instance, I changed your broadcast to have it inside a $timeout with 2 seconds, it would work as expected.
$timeout(function() {
$rootScope.$broadcast('parentEvnt', [1,2,3]);
}, 2000);
Though, you would ideally want to have it on button click or some other scenario.