import Foundation
import UIKit

extension UIViewController {

  /// Finds the first child view controller with the given type, recursively.
  func findChildViewController<T: UIViewController>() -> T? {
    for childViewController in children {
      if let found = childViewController as? T {
        return found
      }
      if let found: T = childViewController.findChildViewController() {
        return found
      }
    }
    return nil
  }

}