Firbase push notification helper class

FCMHandler.js

require('dotenv').config();
const FCM = require('fcm-node');
const serverKey = process.env.GOOGLE_API_KEY;
const fcm = new FCM(serverKey);

class FCMHandler {

    static sentToTopic(topic, flag, message) {
        const msg = {
            to: `/topics/${topic}`,
            notification: {
                title: topic,
                body: topic
            },

            data: {
                title: topic,
                flag: flag,
                data: message
            }
        };
        this.send(msg);
    }

    static send(message) {
        fcm.send(message, function (err, response) {
            if (err) {
                console.log("Something has gone wrong!");
            } else {
                console.log("Successfully sent with response: ", response);
            }
        });
    }
}

module.exports = FCMHandler;