ViewController conforms WKSMH and WKND

vc.swift

extension ViewController: WKScriptMessageHandler, WKNavigationDelegate {
  
  func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
    //This function handles the events coming from javascript. We'll configure the javascript side of this later.
    //We can access properties through the message body, like this:
    guard let response = message.body as? String else { return }
    print(response)
  }
  
  func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
    //This function is called when the webview finishes navigating to the webpage.
    //We use this to send data to the webview when it's loaded.
  }
}