Easy way to show UIAlertController with Builder Pattern

UIAlertControllerX.swift

extension UIAlertController {
	
	// MARK: - Typealias
	
	typealias Alert = UIAlertController
	typealias Action = UIAlertAction
	typealias Block = ((Alert) -> Void)?
	
	// MARK: - Static function
	
	static func alertOkay(title: String, message: Any = "", completion: Block = nil) {
		UIAlertController.Builder()
			.withTitleAndMessage(title: title, message: message)
			.addOkAction(completion: completion)
			.show()
	}
	
	static func alertOkayCancel(title: String, message: Any = "", completion: Block = nil) {
		UIAlertController.Builder()
			.withTitleAndMessage(title: title, message: message)
			.addCancelAction()
			.addOkAction(completion: completion)
			.show()
	}
	
	static func alertTextField(title: String,
							   message: Any = "",
							   numberOfField: Int = 1,
							   placeholders: [String] = [],
							   isSecureTexts: [Bool] = [],
							   completion: Block = nil) {
		UIAlertController.Builder()
			.withTitleAndMessage(title: title, message: message)
			.withTextField(numberOfField: numberOfField, placeholders: placeholders, isSecureTexts: isSecureTexts)
			.addCancelAction()
			.addOkAction(completion: completion)
			.show()
	}
	
	// MARK: - Builder
	
	class Builder {
		
		private var alert: Alert! = Alert(title: "", message: "", preferredStyle: .alert)
		
		@discardableResult
		func withTitleAndMessage(title: String = "", message: Any = "") -> Self {
			alert.title = title
			if let message = message as? String {
				alert.message = message
			}
			if let attributedMessage = message as? NSAttributedString {
				alert.setValue(attributedMessage, forKey: "attributedMessage")
			}
			return self
		}
		
		@discardableResult
		func withTextField(numberOfField: Int = 1, placeholders: [String] = [], isSecureTexts: [Bool] = []) -> Self {
			for i in 0 ..< numberOfField {
				alert.addTextField { tf in
					if placeholders.count == numberOfField {
						tf.placeholder = placeholders[i]
					}
					if isSecureTexts.count == numberOfField {
						tf.isSecureTextEntry = isSecureTexts[i]
					}
				}
			}
			return self
		}
		
		@discardableResult
		func addOkAction(completion: Block = nil) -> Self {
			return addAction(title: "Okay", completion: completion)
		}
		
		@discardableResult
		func addCancelAction(completion: Block = nil) -> Self {
			return addAction(title: "Cancel", style: .cancel, completion: completion)
		}
		
		@discardableResult
		func addAction(title: String, style: UIAlertAction.Style = .default, completion: Block = nil) -> Self {
		  let action = Action(title: title, style: style) { _ in
				completion?(self.alert)
				self.alert = nil	// Avoid leak
			}
			alert.addAction(action)
			return self
		}
		
		func show(completion: (() -> Void)? = nil) {
			DispatchQueue.main.async {
				UIApplication.shared.keyWindow?.rootViewController?.present(self.alert, animated: true, completion: completion)
			}
		}
		
	}
	
}