angular.js $scope.$broadcast, $scope.$emit, $rootScope.$broadcast what to use?
I'm building a search directive which I want multiple other directives of my application to be able to listen for changes to the text search.
I am trying to understand the difference between broadcast and emit, and what is best to suit my purposes.
As I understand it, the difference between $broadcast and $emit is that $broadcast goes down the scope tree only, and that $emit goes up the scope tree.
Up to this point I've been using $rootScope.$broadcast for my events, which for the most part have been global in scope. Is this the right way of doing things? Should I be concerned if I have too many rootScope.$broadcast events? Or is that a non-issue.
Generally, you shouldn't inject $rootScope all over the place. It can often becomes a crutch and you'll end up having a lot of "global variables"
I'd either build a service that abstracts the $rootScope.broadcast call, or simply use databinding instead:
<my-directive text-search="foo"></my-directive>
with a controller like:
.directive('myDirective', [function() {
return {
link: function($element, $scope, $attrs) {
$scope.$watch($attrs.textSearch, function(newValue, oldValue) {
// Do stuff here...
});
}
};
}]);
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