Using Firebase Cloud Messaging as a pub/sub service

Firebase Cloud Messaging (FCM) can be used not only for sending push notifications but also as a publish/subscribe (pub/sub) service in a React application. The process involves setting up FCM on Firebase Console, integrating it into a React app via the Firebase SDK, and handling messages through the Firebase messaging service. A pub/sub system facilitates stateless server-client communication by allowing a browser to listen to a particular topic while the server sends messages to it, which are then processed by the client. This setup includes creating a Firebase project, acquiring credentials, and configuring the React app with Firebase. The tutorial explains setting up the Firebase SDK, creating helper functions for message handling, and using the BroadcastChannel API to synchronize messages across different delivery modes without triggering unnecessary notification badges. It also demonstrates how to publish messages using HTTP requests and manage them within the application, offering a seamless way to achieve server-client communication using FCM.