(Need Help) Tracking OneSignal Push Subscriptions

[Nick]

Is anyone using OneSignal that could tell me how to accurately track when someone allows push notifications on a landing page?

Currently, I'm using the following Javascript, and it's tracking most of the subscriptions, but for some reason, it's not tracking all of them:

OneSignal.on('notificationPermissionChange', function (permissionChange) {
         var  currentPermission = permissionChange.to;
         switch (currentPermission)  {
           case 'granted':
              console.log('✅  Permission - ALLOWED');
              break;
            case 'denied':
              console.log('❌ Permission - DENIED');
              break;
            case 'default':
              console.log('😭 Permission -  CLOSED');
              break;
         }
       });

Is there a better way (i.e. different method) to track this?

Edit: btw, here are the docs