Sending Emails Using Node.js

Introduction

Email communication is a fundamental aspect of modern life and business. With Node.js, developers have a powerful tool at their disposal for automating tasks, including sending emails. Nodemailer, a popular Node.js module, simplifies the process of integrating email functionality into applications. In this guide, we'll explore how to send emails using Node.js with the help of Nodemailer, a module for Node.js applications to allow easy email sending.

Prerequisites

Before we dive into the code, ensure you have the following prerequisites:

• Node.js installed on your system
• An understanding of JavaScript and Node.js basics
• An email account for sending emails
• Basic knowledge of Express.js (optional)

Setting Up Nodemailer

First, install the Nodemailer and multer packages in your Node.js project using npm or yarn:

bash
npm install nodemailer
npm install multer

Setting environment variables

Then, create a .env file in your project directory to store sensitive information like email credentials:

dotenv
EMAIL_HOST=your_email_host
EMAIL_PORT=your_email_port
EMAIL_USERNAME=your_email_username
EMAIL_PASSWORD=your_email_password

Replace your_email_host, your_email_port, your_email_username, and your_email_password with your email provider's SMTP details.

Writing the Code

As in this example I am using Express.js we should make router and controller for our API. Lets start with router which will

Setting up Express Router

Now, let's write the Node.js code to send emails. Here's an example function using Express.js for handling email sending requests. In more advanced example I added middelware for validation and token verification, but we can skip it for now. If we want user to be able to attach files when sending email, we can use multer for easy file uploading.

javascript
// emailRoutes.js

const express = require('express');
const router = express.Router();
require('dotenv').config();
const verifyToken = require('../../middleware/verifyToken');
const upload = require('../../libs/multer');
const { emailSenderValidation, emailContactValidation } = require('../../middleware/mailerValidation');
const { sendNotifyPlainEmail } = require('../../controllers/email/emailController');

// POST route for sending notification emails with plain text
router.post('/notify/plain', upload.any('files'), verifyToken, emailSenderValidation, sendNotifyPlainEmail);

module.exports = router;

Controller Functions

Now, let's define the controller functions for handling email sending in emailController.js:

javascript
const nodemailer = require("nodemailer");
require('dotenv').config();
const path = require('path');
const { validationResult } = require('express-validator');
const { generateSimpleEmail, generateContactEmail } = require('./emailGenerator');

async function sendNotifyPlainEmail(req, res) {
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
        return res.status(400).json({ errors: errors.array() });
    }
    const { to, cc, subject, content } = req.body;

    try {
        const transporter = nodemailer.createTransport({
            host: process.env.EMAIL_HOST,
            port: process.EMAIL_PORT,
            secure: true,
            auth: {
                user: process.env.EMAIL_USERNAME,
                pass: process.env.EMAIL_PASSWORD,
            },
            tls: {
                rejectUnauthorized: true,
            },
        });
        const haveAttachments = req?.files ? req.files.map(file => {
            return {
                filename: file?.originalname,
                path: path.join('uploads', file?.originalname),
                cid: file?.filename
            }
        }) : false;

        const info = await transporter.sendMail({
            from: '"Admin Test 🚀" <office@mail.com>',
            to: to,
            cc: cc,
            subject: subject,
            text: content,
            html: content,
            attachments: haveAttachments ? haveAttachments : ''
        });
        console.log(info.envelope);
        console.log("Message sent: %s", info);
        res.send({ data: `Email sent to ${to}`, messageId: info.messageId }).status(200);
    } catch (exc) {
        console.error('error happened', exc);
        res.status(400).send({ message: `Message was not delivered to ${to}`, error: exc });
    }
}

module.exports = { sendNotifyPlainEmail };

Testing API

Ok now we have our API so we want to test it , easiest way to do is with postman or curl, here is the example for curl :

curl
curl --location 'http://localhost:3000/email/notify/plain' \
--header 'x-api-key: 1111111-1111-111-1111-11111' \
--form 'to="jagetic.bojan@testmail.com"' \
--form 'content="Test 123"' \
--form 'subject="Test Subject"'

After successfully calling our new API we should be able to see response

{"data":"Email sent to jagetic.bojan@testmail.com","messageId":"<2c9cbf8e-25db-e329-11111-1111111@test.com>"}%        

Conclusion

With this code, you can easily send emails using Node.js and Nodemailer. Remember to handle errors gracefully and secure your email credentials properly.

Feel free to customize the code according to your specific requirements and integrate it into your Node.js applications for sending emails effortlessly.