Stop AngularJs from creating new controller/$scope cache and use cached one

Question

Using $routeProvider every time user clicks on a link, a new $scope is being generated. That means all the data is lost. How can i make Angular use the same controller/$scope?

Explanation:

http://jsfiddle.net/mpKBh/1/ (click on links)

<a href='#'>First controller</a>
<a href='#/view'>Second controller</a>

$routeProvider.
  when('/', { template:"{{$id}}",controller: ContentListCtrl}).
  when('/view', {template:"{{$id}}",controller: ContentDetailCtrl}).

P.s. is it possible to know which controller is currently active?

Josh David Miller · Accepted Answer · 2013-03-05 20:33:55Z

4

In AngularJS, $scope is not meant to hold data that persists across your application. For that, you want to use a service that is injected into both controllers. If you provide more detail on what data you're missing across routes, I would be happy to revise this answer to include something a little more actionable.

In re your PS: You can inject the $route service to get information about the current route; the $route.current.controller property will give you the constructor function of the current route.

answered Mar 5, 2013 at 20:33

Josh David Miller

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5 Comments

Jason Aden Over a year ago

This answer is correct. You could also use Angular's $cacheFactory if you have specific data that you would like to cache, but it is definitely correct that $scope gets destroyed when you change routes. If you don't want the $scope destroyed, and using services is not correct for your application, don't use routing and use includes instead.

Artūras Over a year ago

I've implemented this jsfiddle.net/vojtajina/U7Bz9 example for infinite scroll, but when i'm changing routes, loadMore is still left binded, so if I trigger the controller 10 times i have 10 loadMore instances listening and at each scroll there will be 10 requests. So i was hoping that if i could persist the controller i wouldn't receive unnecessary requests. Any work arounds?

Josh David Miller Over a year ago

@n0mercy I'm not sure I follow why you would get so many listeners - or for that matter even more than one. Can you add some routing to this and use some console.log() statements to show what you mean?

Artūras Over a year ago

This is what i was talking about: jsfiddle.net/xrYPb/1 i think the problem is that i'm using window.bind here. Am I right? jsfiddle.net/xrYPb this is the revision that always has 1 listener, but i need to bind to window scroll :/

Artūras Over a year ago

Actually the question in a bit out of scope. Ill make a new thread with this concrete question. How to bind/unbind to 'window' in angular. Because i can't really find anything. Big thanks!

PRB · Accepted Answer · 2014-04-17 16:44:38Z

For those researching how to "unbind" in AngularJS, he is a bit of info (related to the OP's last comment above)

When a view is destroyed, it's basically marked for garbage collection - but it's still there. That is why you are getting multiple requests when a scroll happens - because it's still listening for events.

So the easiest way to deal with this (that I have found, though I'd like to learn of other ways) is to listen for the $destroy event and react on it.

You can "unbind/unlisten" for an event by keeping a reference to what is returned by the $on method. Here is an example taken from a controller:

$scope.systemListener = $rootScope.$on("someEventYouListenTo", function (event, data) {
  console.log('Event received by ' + $scope.name);
});

$scope.$on('$destroy', function () {
    // Remove the listener
    $scope.systemListener();
});

Now those old scopes/views won't react to events anymore.

Hope that helps someone!

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