Angularjs $on called twice

Question

So I have this situation where one controller is emitting the event and the other controller has the listener. Here is the code:

In controller A, I have this method:

$scope.process = function () {
    var taskName = 'process';
    $scope.$emit('process', taskName);
}

In controller B, I have this:

$rootScope.$on('process', function (event, taskName) {
    //Do something here
});

Now whenever I visit other pages on application and comeback to this, the process listener gets created twice. I cannot use controller scope as the event is getting emitted from other controller. How can I destroy listener once it has completed its task? I have also tried $scope.$destroy(). Doesn't really work. What is the correct way of doing this?

I am on Angularjs 1.4.7.

Answer 1

Usually you do it in different way:

$rootScope.$broadcast(...)
...
$scope.$on(...)

Then you do not need to unsubscribe. If you really need for some reason to subscribe to $rootScope, then:

var deregister = $scope.$on(...);
...
deregister(); // destory that listener