app.js

const express = require("express");
const cors = require("cors");
const dotenv = require("dotenv");
const nodemailer = require("nodemailer")
dotenv.config();

const port = process.env.PORT || 3000;

const app = express();

app.use(cors());
app.use(express.urlencoded());
app.use(express.json());

app.listen(port, () => {
  console.log(`Server hosted on http://localhost:${port}`);
});

app.get("/", (req, res) => {
  res.json({ name: "Express Mailer !!" });
});

app.post("/send-mail", (req, res) => {
  const output = `
    <p>You have a new Mail by the Website</p>
    <p>${req.body.subject}</p>
    <h3>Contact Details</h3>
    <pre>
         Name: ${req.body.name}
         Email: ${req.body.email}
    </pre>
    <h3>Subject</h3>
    <p>${req.body.subject}</p>
    <h3>Message</h3>
    <p>${req.body.message}</p>
  `;

  // Transporter for mail
  let transporter = nodemailer.createTransport({
    host: "smtp.gmail.com",
    port: 587,
    secure: false,
    auth: {
      user: process.env.EMAIL_USERNAME, // enter the sender email address in .env file
      pass: process.env.EMAIL_PASSWORD, // enter the sender email password in .env file
    },
    tls: {
      rejectUnauthorized: false,
    },
  });

  // setup email data
  let mailOptions = {
    from: '"New Mail from Website" <yoursendermail@mail.com>', // sender address
    to: "ris8645208@gmail.com", // list of receivers
    subject: `${req.body.subject}`, // Subject line
    html: output, // html body
  };

  // send mail
  transporter.sendMail(mailOptions, (error, info) => {
    if (error) {
      return console.log(error);
    }
    console.log("Message sent: %s", info.messageId);
    console.log("Preview URL: %s", nodemailer.getTestMessageUrl(info));

    res.json({ msg: "Email has been sent" });
  });
});