provide disassociate callback

[clkao]

Make the promise returned by angularFire resolved with a callback that disassociate the instance, by calling dataRef.off and unregistering $scope.$watch.

This breaks the existing promise API. But since angularFire is to bind an object onto scope, it doesn't seem to be useful to get the same value from the promise though.

[anantn]

@clkao - Thanks for sending in the pull request! Before merging it however, I'd like to understand the motivations behind the patch a little better. Since it'll break our API I'm quite hesitant to make the change.

[clkao]

@anantn, the use case is when a controller has a $scope variable bound to specified resource, such $scope.project to /project/foo, you can't change that binding to /project/bar. If you use angularFire to reassociate, content of foo will be overridden by bar. delete $scope.project and reassociate won't work either, because the $watch gets project being updated to null and will delete project/foo. That's why an explicit disassociation api is needed, for both off() the firebase ref and unwatch the scope variable.

[clkao]

Hi, any update on this?

[anantn]

Sorry this got slipped through the cracks. The API makes sense now, thanks for the explanation and pull request!

[robertmaxwell]

How do you go about using this "disassociation api"?

I am trying to switch which angular resources I am using within a controller (exactly like @clkao's example use case) and it is deleting the data in Firebase.

How do I first disassociate the Firebase connection and Angular watcher so that I can assign a new resource/reference without this deletion?

thanks in advance

[clkao]

here's what i do before associating an entry:

// in $scope.$watch projectName
if (typeof $scope.cleanup === 'function') {
  $scope.cleanup();
}
promise = angularfire(hub.root.child("projects/" + projectName), $scope, 'project', {});
return promise.then(function(cb){
  return $scope.cleanup = cb;
});

@robertdimarco would you like to help adding that to the document?

full usage can be found at: https://github.com/g0v/hack.g0v.tw/blob/master/app/app/hub.ls#L93

[adamjgrant]

Also, @clkao, I tried implementing your solution, which did not work for me. Maybe I'm putting it in the wrong place? What is $scope.$watch, is that AngularFire or Angular? Whatever it is, I don't have or nor knew I needed it from the documentation.

Thanks.

[adamjgrant]

Related: http://stackoverflow.com/questions/19482108/prevent-items-in-scope-from-writing-to-a-different-users-records