How to unsubscribe to a broadcast event in angularJS. How to remove function registered via $on

You need to store the returned function and call it to unsubscribe from the event.

var deregisterListener = $scope.$on("onViewUpdated", callMe);
deregisterListener (); // this will deregister that listener

This is found in the source code :) at least in 1.0.4. I'll just post the full code since it's short

/**
  * @param {string} name Event name to listen on.
  * @param {function(event)} listener Function to call when the event is emitted.
  * @returns {function()} Returns a deregistration function for this listener.
  */
$on: function(name, listener) {
    var namedListeners = this.$$listeners[name];
    if (!namedListeners) {
      this.$$listeners[name] = namedListeners = [];
    }
    namedListeners.push(listener);

    return function() {
      namedListeners[indexOf(namedListeners, listener)] = null;
    };
},

Also, see the docs.

Looking at most of the replies, they seem overly complicated. Angular has built in mechanisms to unregister.

Use the deregistration function returned by $on :

// Register and get a handle to the listener
var listener = $scope.$on('someMessage', function () {
    $log.log("Message received");
});

// Unregister
$scope.$on('$destroy', function () {
    $log.log("Unregistering listener");
    listener();
});

This code works for me:

$rootScope.$$listeners.nameOfYourEvent=[];