Node JS : Express JS : Formidable : Nodemailer - How can i upload a html template on contact form and send it using Nodemailer?

I have a contact form and i want to upload a html template using the input file and send it with Nodemailer. I have used formidable to get a temporary path but im not able to pass this parameter to the HTML tag of sendMail. How can i archive this ?

This is my current app.js

const express = require('express');
const formidable = require('formidable');
var fs = require('fs');
const port = process.env.PORT || 3000;
const app = express();

app.get('/', (req, res) => {
    res.send(`<h2>With<code>"express"</code>
    npmpackage</h2>
    <form action="/api/upload" enctype="multipart/form-data" method="post">
    <div>Text field title:<input type="text" name="title"/></div>
    <div>File:<input type="file" name="someExpressFiles" multiple="multiple"/>
    </div>
    <input type="submit" value="Upload"/>
    </form>`);
});

app.post('/api/upload', (req, res, next) => {
    const form = new formidable.IncomingForm({ multiples: true });
    form.parse(req, (err, fields, files) => {
        if (err) { next(err); return; }
        res.json({
            fields, files
        });
    });

    async function main() {
        let testAccount = await nodemailer.createTestAccount();
        let transporter = nodemailer.createTransport({
            host: "smtp.ethereal.email",
            port: 587,
            secure: false,
            auth: {
                user: testAccount.user,
                pass: testAccount.pass,
            },
        });

        let info = await transporter.sendMail({
            from: '"Fred Foo 👻" <foo@example.com>',
            to: "bar@example.com, baz@example.com",
            subject: "Hello ✔",
            text: "Hello world?",
            html: "<b>Hello world?</b>",
        });

        console.log("Message sent: %s", info.messageId);
        console.log("Preview URL: %s", nodemailer.getTestMessageUrl(info));
    }
});

app.listen(port, () => {
    console.log('Server listening on http://localhost:3000...');
}).timeout = 1000 * 60 * 10;

Solved it :

const express = require('express');
const formidable = require('formidable');
const nodemailer = require("nodemailer");
const fs = require('fs');
const path = require('path')
const port = process.env.PORT || 3001;
const app = express();
app.use('/public', express.static(path.join(__dirname, 'public')));
app.set('views', './views');
app.get('/', (req, res) => {
    fs.readFile('views/index.html', function (err, data) {
        res.writeHead(200, { 'Content-Type': 'text/html', 'Content-Length': data.length });
        res.write(data);
        res.end();
    });
});

app.post('/', (req, res, next) => {
    const form = new formidable.IncomingForm({ multiples: true });
    form.parse(req, (err, fields, files) => {
        if (err) { next(err); return; }
        // res.json({
        //     fields, files
        // });
        var expressPath = fs.readFileSync(files.expressFiles.filepath).toString();
       async function main() {
        let testAccount = await nodemailer.createTestAccount();
        let transporter = nodemailer.createTransport({
            host: "smtp.ethereal.email",
            port: 587,
            secure: false,
            auth: {
                user: testAccount.user,
                pass: testAccount.pass,
            },
        });

        let info = await transporter.sendMail({
            from: '"Fred Foo 👻" <foo@example.com>',
            to: "bar@example.com, baz@example.com",
            subject: "Hello ✔",
            text: "Hello world?",
            html: "<b>Hello world?</b>",
        });
            console.log("Message sent: %s", info.messageId);
            console.log("Preview URL: %s", nodemailer.getTestMessageUrl(info));
            res.sendFile(__dirname + '/views/success.html')
            msg = true;
        }

        main().catch(console.error);


    });
});


app.listen(port, () => {
    console.log('Server listening on http://localhost:3000...');
}).timeout = 1000 * 60 * 10;