How do I detect when embedded Youtube video is playing? - nativescript

Question

UPDATE (July 2020): I was able to get a mostly working version of this. See my answer to the related question here.
In my angular Nativescript iOS app, I have a webview set up to play youtube videos. Following a method similar to this question here, I can get the youtube video to load and play automatically, using the Youtube Iframe API. But how do I detect when the video actually starts playing (after it is loaded)?
The Iframe API has events for this purpose, like "onStateChange". But, because my youtube code is "stuck" inside the webview, I am currently not able to read when events are fired from that webview.
In Nativescript, there is a nativescript-webview-interface plugin for this purpose, but I can't get it to work. I have put my code below. If that is the way to go, what is the correct code to get it working?
(I don't want to use the nativescript-youtube plugin because that brings in youtube's quotas, which are regularly shrinking. )
Code I Have Tried:
To get the youtube player to activate, I have put all of the relevant youtube code inside the webview. That works to play the video, but not yet to get the event of when the player starts playing. To do what I want to do, I need to have some way of inserting that code into my app WITHOUT trapping it in the webview. Or, have some way of communicating inside the webview.
To try to communicate with the webview, I have tried the nativescript-webview-plugin:
$ tns plugin add nativescript-webview-interface
html:
<web-view src="{{youtubeCode}}" #webView ></web-view>
ts:
import {WebView, LoadEventData} from "tns-core-modules/ui/web-view";
let webViewInterfaceModule = require('nativescript-webview-interface');
...
export class ...{
#ViewChild('webView') webView: ElementRef;
public youtubeCode = [code that youtube provides in its IFrame API]
ngOnInit(): void {
this.setupWebViewInterface();
}
setupWebViewInterface() {
let webView: WebView = this.webView.nativeElement;
this.oWebViewInterface = new webViewInterfaceModule.WebViewInterface(webView, '~/www/index.html');
this.youtubeListen()
}..
youtubeListen(){
this.oWebViewInterface.on('onStateChange', (eventData)=>{ //'onStateChange' is the event provided in the Youtube Iframe API
console.log('event data = ' + eventData) //***this is the key part I want to work.
});
}
RESULT: ERROR TypeError: undefined is not an object (evaluating 'this.webView.ios.constructor')
This is a problem in the plugin's index.ios.js file. If I comment out the offending line, then the errors go away, but then nothing happens
..