Correct way to retrieve token for FCM - iOS 10 Swift 3

Question

i had implement Firebase with FirebaseAuth/FCM etc and did sent notification successfully through Firebase Console.

However i would need to push the notification from m

Answer 1

The tokenRefreshNotification function doesn't always get called when launching the app.

However, when placing the code inside the regular didRegisterForRemoteNotificationsWithDeviceToken delegate function, I can get the token every time:

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    if let refreshedToken = InstanceID.instanceID().token() {
        print("InstanceID token: \(refreshedToken)")
    }
}

(Swift 3 + Firebase 4.0.4)