AngularJS : broadcast event from directive

Question

I've seen people doing this from wherever in their code:

$rootScope.$broadcast('someEvent', someParameter);  

and then in some controller:

$rootScope.$on('someEvent', function(event, e){ /* implementation here */ }); 

Now, I'd like to broacast an event from a directive. Is it good practice to broadcast it at rootScope level ? I would like to handle this event in a controller. Can I use $scope, or do I still have to listen on $rootScope ?

Answer 1

In my case, I just want to broadcast an event from a directive to the controller of the view, in which I use the directive. Does it still make sense to use broadcast then?

I would have the directive call a method on the controller, which is specified in the HTML where the directive is used:

For a directive that uses an isolate scope:

<div my-dir ctrl-fn="someCtrlFn(arg1)"></div>  app.directive('myDir', function() {   return {     scope: { ctrlFn: '&' },     link: function(scope, element, attrs) {        ...        scope.ctrlFn({arg1: someValue});     } 

For a directive that does not use an isolate scope:

<div my-dir ctrl-fn="someCtrlFn(arg1)"></div>  app.directive('myDir', function($parse) {   return {     scope: true,  // or no new scope -- i.e., remove this line     link: function(scope, element, attrs) {        var invoker = $parse(attrs.ctrlFn);        ...        invoker(scope, {arg1: someValue} );     } 

Answer 2

It's usually a good idea not to use the $rootScope as it's global and you shouldn't pollute it unless you really know what you're doing. I would recommend that you read this article about communication between services, directives and controllers.