Cloud function for sending notification to android, ios and amazon

index.js

function sendAlertNotification(userId, instanceId, notificationKey) {
  
  // Notification details.
  const payload = {
    notification: {
      title: `Price Alert`,
      body: 'Body',
      sound: 'default',
      icon: 'ic_alerts',
      android_channel_id: "alerts_channel",
      tag: 'unique_key'
    }
  };
  // Set the message as high priority and have it expire after 24 hours.
  var options = {
    priority: "high",
    timeToLive: ttl,
    mutableContent: true,
  };

  return sendNotification(userId, instanceId, notificationKey,  payload, options);
}

utils.js

'use strict';

const admin = require('firebase-admin');
const serviceAccount = require('../service-account.json');
const firebaseAppOptions = {
  credential: admin.credential.cert(serviceAccount),
  databaseURL: `https://${process.env.GCLOUD_PROJECT}.firebaseio.com`
};
var firebaseApp = admin.initializeApp(firebaseAppOptions);
const RSVP = require('rsvp');
const Logging = require('@google-cloud/logging');
const logging = Logging();
const IAM_USER = "XXXX";
const API_KEY = "XXXX";
const SENDER_ID = "XXXX";
const FCM_SERVER_KEY = "XXXX";


//ADM
const ADM_CLIENT_ID = "XXXX";
const ADM_CLIENT_SECRET = "XXXX";
var adm = require('node-adm');
var options = {
  client_id: ADM_CLIENT_ID,
  client_secret: ADM_CLIENT_SECRET
};
var admSender = new adm.Sender(options);

function sendNotification(userId, instanceId, notificationKey, payload, options) {
  const comboKey = payload.notification.tag;
  notificationKey = "";
  if (instanceId.startsWith('amzn1')) {
    payload.expiresAfter = options.timeToLive;
    return sendADMNotification(userId, instanceId, payload);
  }
  const sendRequest = notificationKey ? admin.messaging().sendToDeviceGroup(notificationKey, payload, options)
  : admin.messaging().sendToDevice(instanceId, payload, options)

  return sendRequest.then(response => {
    if (notificationKey) {
      if (response.failureCount > 0 || response.successCount) {
        const failedIds = response.failedRegistrationTokens;
        reportError("error", {user: userId, tokens: failedIds});
      }
      return logInfo("Successfully sent message group message", {user: userId, key : comboKey});
    } else {
      RSVP.all(response.results.map((result, index) => {
        const error = result.error;
        if (error) {
          reportError(error, {user: userId, token: instanceId});
          if (error.code === 'messaging/invalid-registration-token' ||
              error.code === 'messaging/registration-token-not-registered') {
            return admin.database().ref(`/users/${userId}/instanceId`).remove().then(result => {
              logInfo('Removed invalid instanceId', {user: userId, token: instanceId});
              return admin.database().ref(`/users/${uid}/clients`).once('value').then(clientSnapshot => {
                clientSnapshot.forEach(function(dataSnapshot) {
                  const clientKey = dataSnapshot.key;
                  const childInstanceId = dataSnapshot.val().instanceId;
                  if(childInstanceId == instanceId) {
                    return admin.database().ref(`/users/${userId}/clients/${clientKey}`).remove();
                  }
                });
              });
            })
            .catch(error => {
              return reportError(error, {user: uid, type: 'database_write', context: 'delete instanceId'});
            });
          }
        }
        return logInfo("Successfully sent message", {user: userId, key : comboKey});
      }));
    }
  })
  .catch(error => {
    return reportError(error, {user: userId, token: instanceId, type: 'fcm_message'});
  });
}

function sendADMNotification(userId, instanceId, payload) {
  return admSender.send(payload, instanceId, function(error, result) {
    if (error || result.error) {
      return reportError(error, {user: userId, token: instanceId});
    } else {
      return logInfo("Successfully sent message", {user: userId, response : result});
    }
  });
}