It's an example how to push notification by the firebase cloud messaging.
To run the server you need to open the terminal/console to the project directory and use next commands.
cd <PROJECT_DIRECTORY>/backend
npm install
the firebase cloud messging has to be set up. After the firebaseConfig and serviceAccount have to be taken from the project settings. Copy config.example.js and rename it and change the name config.js and copy the serviceAccount and firebaseConfig to from the firebase cloud messaging to config.js Use the next command to run project.
npm start
Open the http://localhost:8080 (by default). The button sends the push notification to onMessage. The firebase cloud messaging dashboard has the testing page to send the push notification to http://localhost:8080.
the frontend app runs similar as the backend Use next commands:
cd <PROJECT_DIRECTORY>/frontend
npm install
npm start
Pay attention, for listening to the background message the firebase cloud message needs only service worker. If someone wants to listen the background notification it needs to check the file which is located to
<PROJECT_DIRECTORY>/frontend/public/firebase-messaging-sw.js