Detecting page unload in angularjs

Question

I have a javascript object which I need global to my angularjs application. When the application is about to be unloaded (due to a page refresh or some other scenario), I would like to persist the object to browser storage. I believe adding the object to $rootScope would fulfill the first requirement of making the object global, but writing the object to storage during the onbeforeunload event, would require access to the $rootScope variable. Is it possible to detect a page unload event in angularjs?

Solution

This should do it, but I also suggest avoiding $rootScope as global state is discouraged, and you might also wrap localStorage in a service so that it can be injected and mocked for testing.

.run([
  '$window',
  '$rootScope',
  function($window, $rootScope) {
    $window.addEventListener('beforeunload', function() {
      localStorage.myValue = $rootScope.myValue;
    });
  }
]);

Comments

[user1491636]

Thanks. And would the event for page completed loading be load?

[m59]

@user1491636 I don't think you should be using that event. If you want something to run at the beginning of your Angular app, just put it in a run block as in my example here.

[Ivan Ferrer]

Your solution does not solve the problem, because even by clicking cancel it is called.

[m59]

@IvanFerrer Clicking cancel on what? Nothing in the post or my answer involves any buttons, that I know of.