React Native: add keyboard shortcuts to iOS app

Question

So I was trying add keyboard shortcuts to my React Native iOS app. So that users can with an external keyboard on the iPad can take advantage of those shortcuts.

I've created an AppDelegate.swift and RootViewController.swift to work only with swift in my React Native app. So far my basic app is running. It also compiles with the code for the KeyCommands added to RootViewController but that doesn't trigger the action when pressing cmd + s or display available commands when pressing and holding the cmd key on the iPad.

AppDelegate.swift

import Foundation

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

 var window: UIWindow?

 func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions [UIApplication.LaunchOptionsKey: Any]?) -> Bool {


   var rootView: RootViewController = RootViewController()

   self.window = UIWindow(frame: UIScreen.main.bounds)
   var rootViewController = UIViewController()

   rootViewController = rootView

   self.window!.rootViewController = rootViewController;
   self.window!.makeKeyAndVisible()

  return true
 }
}

RootViewController.swift

import Foundation
import UIKit


class RootViewController: UIViewController {

  var bridge: RCTBridge!

  override func viewDidLoad() {
    super.viewDidLoad()

    let jsCodeLocation = NSURL(string: "http://localhost:8081/index.bundle?platform=ios&dev=true")

    let rootView = RCTRootView(bundleURL:jsCodeLocation as URL!, moduleName: "tinyWhaleApp", initialProperties: nil)

    self.bridge = rootView?.bridge

    self.view = rootView

  }


  override func becomeFirstResponder() -> Bool {
    return true
  }

  override var keyCommands: [UIKeyCommand]? {
    return [
      UIKeyCommand(input: "s", modifierFlags: [.command], action: "saveFile:", discoverabilityTitle: "Save"),
    ]
  }

  func saveFile(sender: UIKeyCommand) {
    print("saving file")
  }
}

If someone could help me getting keyboard shortcuts working on the iPad with an external keyboard, that would be great.