Firebase functions - create new user in db when new user is added to auth. and send mail

gistfile1.txt

'use strict';

const admin = require('firebase-admin');
const functions = require("firebase-functions");
const nodemailer = require('nodemailer');


admin.initializeApp();

const db = admin.firestore();

exports.helloWorld = functions.https.onRequest((request, response) => {
    response.send("<h1>Hello from Firebase!</h1>");
});

const gmailEmail = "email@gmail.com";
const gmailPassword = "password";
const mailTransport = nodemailer.createTransport({
  service: 'gmail',
  auth: {
    user: gmailEmail,
    pass: gmailPassword,
  },
});

exports.sendWelcomeEmail = functions.auth.user().onCreate(user => {
    
    console.log("user is...: ", user );
    console.log("email is...: ", user.email );
   
    const mailOptions = {
        from: `"${user.uid}" <email@gmail.com>`,
        to: "email@gmail.com",
        subject: `Welcome ${user.uid}`,
        html: `Welcome ${user.uid}`
    };

	var userObject = {
		displayName : "Name",
		email : user.email,
		createdOn : user.metadata.creationTime
    };
    
    // this is working so dont change it!!
    try {
        mailTransport.sendMail(mailOptions);
        console.log(`mail sent`);    
    } catch(error) {
        console.error('There was an error while sending the email:', error);
    }

    return db.doc(`users/${user.uid}`).set(userObject);

});