AlertExtension use in your project

AlertExtension.swift

//
//  AlertExtension.swift
//
//
//  Created by vikrant-Ios on 01/12/17.
//  Copyright © 2017 vikrant-Ios. All rights reserved.
//

import Foundation

// Snippet

typealias AlertActionHandler = ((UIAlertAction) -> Void)

extension UIAlertControllerStyle {
    
    func controller(title: String, message: String, actions: [UIAlertAction]) -> UIAlertController {
        let aController = UIAlertController(
            title: title,
            message: message,
            preferredStyle: self
        )
        actions.forEach { aController.addAction($0) }
        return aController
    }
}

extension String {
    
    func alertAction(style: UIAlertActionStyle = .default, handler: AlertActionHandler? = nil) -> UIAlertAction {
        return UIAlertAction(title: self, style: style, handler: handler)
    }
}

viewController.swift

// how to use alertcontroller in viewcontroler file
let alertController = UIAlertControllerStyle.alert.controller(
   title: "Hi",
   message: "Everyting will be fine.",
   actions: [
       "No".alertAction(),
       "Yes".alertAction { _ in /* logic here */
                           print("action perform here")}
   ])

self.navigationController?.present(alertController, animated: true)