How to send an email from Node.js using Gmail

config.js

module.exports = {
  email: {
    address: 'youraddress@gmail.com',
    password: 'clever-password'
  }
};

email-from-node-using-gmail.js

/*
This module will accept a recipient email address, subject and body of email (in HTML format),
and send it via a Gmail address.
*/

const nodemailer = require('nodemailer');
const config = require('../config');

module.exports = (to, subject, html) => {
  return new Promise((resolve, reject) => {
    const transporter = nodemailer.createTransport({
      service: 'Gmail',
      auth: {
        user: config.email.address,
        pass: config.email.password
      }
    });

    const mailOptions = {
      from: config.email.address,
      to,
      subject,
      html
    };

    transporter.sendMail(mailOptions, (error, info) => {
      if (error) {
        reject(error);
      } else {
        resolve(`Message sent: ${info.response}`);
      }
    });
  });
};