How to cancel UserNotifications

For cancelling all pending notifications, you can use this:

UNUserNotificationCenter.current().removeAllPendingNotificationRequests()

For cancelling specific notifications,

UNUserNotificationCenter.current().getPendingNotificationRequests { (notificationRequests) in
   var identifiers: [String] = []
   for notification:UNNotificationRequest in notificationRequests {
       if notification.identifier == "identifierCancel" {
          identifiers.append(notification.identifier)
       }
   }
   UNUserNotificationCenter.current().removePendingNotificationRequests(withIdentifiers: identifiers)
}

The way same UNNotification is identify are base on the identifier passed when you create the UNNotificationRequest.

In your example above,

let request = UNNotificationRequest(identifier: "myNotif", content: notif, trigger: dateTrigger)

You have actually hardcoded the identifier to be "myNotif". This way, whenever you want to delete the already set notification you can do this:

UNUserNotificationCenter.current().removePendingNotificationRequests(withIdentifiers: "myNotif")

However, do take note that when you hardcode the identifier, every time when you add a request to UNUserNotificationCenter the notification is actually being replaced.

Example, if you scheduled a "myNotif" request set on 1 minute later but you call another function to schedule a "myNotif" at 1 hour later it will be replaced. Therefore only the latest "myNotif" at one hour later will be in the pendingNotificationRequest.