Define custom NSNotification.Name

NSNotificationName+Extension.swift

// NSNotification.Name拡張
extension NSNotification.Name {
    static let sample = Notification.Name(rawValue: "sample")
//    static let hoge = Notification.Name(rawValue: "hoge")
//    static let fuga = Notification.Name(rawValue: "fuga")
}

/////////////////////////////////////////////////////////////////////////////////////////////

// 通知発行側コード
class DetailViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    
    @IBAction private func onNotifyButtonClick(_ sender: UIButton) {
//        NotificationCenter.default.post(name: NSNotification.Name(rawValue: "sample"), object: nil, userInfo: nil)
        NotificationCenter.default.post(name: .sample, object: nil)
    }
}

/////////////////////////////////////////////////////////////////////////////////////////////

// 通知受信側コード
class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
//        NotificationCenter.default.addObserver(self, selector: #selector(onSampleNotified(_:)), name: NSNotification.Name(rawValue: "sample"), object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(onSampleNotified(_:)), name: .sample, object: nil)
    }
    
    deinit {
//        NotificationCenter.default.removeObserver(self, name: NSNotification.Name(rawValue: "sample"), object: nil)
        NotificationCenter.default.removeObserver(self, name: .sample, object: nil)
    }
    
    func onSampleNotified(_ notification: NSNotification) {
        print("Notification button pushed")
    }
}