AngularJS $rootScope.$emit service pattern

gistfile1.js

// pattern for creating servicesto communicate efficiently between angular components

	services.factory('changeService',  ['$rootScope', 
		function ($rootScope) {

	    var changeService = {};

	    // use changeService.changed(action) in controller to act on changes
	    changeService.changed = function(callback){
	    	$rootScope.$on('change', callback);
	    };
	    
	    //  use changeService.change() to notify application of changes (emit has way better performance than broadcast)
	    changeService.change = function(){
	    	$rootScope.$emit('change');
	    };
	    
	    return notifyService;
	}]);