I found it quite strange that AngularJS does not have possibility to watch several Angular-events, i.e.:

[javascript]
$scope.$on([‘user.login’, ‘user.logout’], callback);
[/javascript]

and I decided to extend $on method, to make it handle such case:

[javascript]
var $onOrigin = $rootScope.$on;
$rootScope.$on = function(names, listener) {
var self = this;

if (!angular.isArray(names)) {
names = [names];
}

names.forEach(function(name) {
$onOrigin.call(self, name, listener);
});

};
[/javascript]

Sandbox for this code you can find here.