Progressive Web Apps with React

Writing our Cloud function

First, we can initialize our app, as follows:

const functions = require('firebase-functions');const admin = require('firebase-admin');admin.initializeApp(functions.config().firebase);

Cloud functions = code run in response to events, so what's our event?

We want to notify the user when a new message is created. So, the event is a new message, or, more specifically, when a new entry is created in the messages table of our database.

We'll define the export of our index.js to be a function called sendNotifications, which defines a listener for the onWrite event of /messages:

exports.sendNotifications = functions.database  .ref('/messages/{messageId}')  .onWrite(event => {});

Everything else in this section will take ...