add message layer for backward compatibility

src/microsoft-trydotnet-editor/src/index.ts

@@ -8,6 +8,7 @@ import './index.css';
 import * as messageBus from './messageBus';
 import * as rxjs from 'rxjs';
 import * as monacoAdapterImpl from './monacoAdapterImpl';
+import { CommandCancelledType, CommandFailedType, CommandSucceededType, SubmitCodeType } from '@microsoft/dotnet-interactive';
 
 if (window) {
 
@@ -29,7 +30,21 @@ if (window) {
 	const kernel = factory.createWasmProjectKernel();
 	const tdnEditor = new tryDotNetEditor.TryDotNetEditor(mainWindowMessageBus, kernel);
 
+	// for messaging api backward compatibility
+	kernel.subscribeToKernelEvents((event) => {
+		if ((event.eventType === CommandSucceededType || event.eventType == CommandFailedType || event.eventType == CommandCancelledType) && event.command?.commandType === SubmitCodeType) {
+			window.postMessage({
+				type: "NOTIFY_HOST_RUN_READY"
+			}, '*');
+		}
+	});
+
 	tdnEditor.editor = new monacoAdapterImpl.MonacoEditorAdapter(editor);
 
 	window['trydotnetEditor'] = tdnEditor;
+
+	// for messaging api backward compatibility
+	window.postMessage({
+		type: "NOTIFY_HOST_EDITOR_READY"
+	}, '*');
 }