I'm trying to create a small PWA with JavaScript (just jQuery) that uses Firebase Cloud Messaging. I Initialize messaging like this:

<script type="module">
	import { initializeApp } from "<https://www.gstatic.com/firebasejs/9.14.0/firebase-app.js>";
	import { getMessaging, getToken, onMessage } from "<https://www.gstatic.com/firebasejs/9.14.0/firebase-messaging.js>";

	// Your web app's Firebase configuration
	const firebaseConfig = {
		apiKey: "<Api-Key>",
		authDomain: "<Domain>",
		projectId: "<ProjectId>",
		storageBucket: "<Bucket>",
		messagingSenderId: "<Sender-Id>",
		appId: "<App-Id>",
		name: "<App-Name>"
	};

	// Initialize Firebase
	const app = initializeApp(firebaseConfig);
	const messaging = getMessaging();

	getToken( messaging, { vapidKey: '<Public-Key>' } )
	.then((currentToken) => {
		if (currentToken) {
			window.localStorage.setItem( 'fbToken', currentToken );
		} else {
			console.log('No registration token available. Request permission to generate one.');
		}
	}).catch((err) => {
		console.log('An error occurred while retrieving token. ', err);
	}); 

	onMessage(messaging, payload => {
		console.log("Message received. ", payload);
		const { title, ...options } = payload.notification;
	});
</script>

On clicking a button the app reads the token from local storage and sends an ajax request to CF which then uses

cfhttp()

to send a message to Firebase with this request body:

{
    "to" : arguments.data.fbToken
  , "notification" : {
        "message": arguments.data.msg
      , "title": "Greetings"
    }
}

The result of the

cfhttp()

call shows

success: 1

(plus things like

multicast_id

and

message_id

), so I assume that I did things right so far. Yet the

onMessage()

event handler never fires, and I don't know whether the message never arrives or if there is a different problem. Any ideas or hints?

From your example onmessage is a global method? Shouldn't it be attached to your request