Nodejs server without express or any framework. Handle GET and POST

server.js

/*
*I will share how you can achieve the below:
*Handle GET and POST requests in Nodejs without using a framework.
*Serve static files from a public folder (css, js, images).
*/
const http = require('http')
const fs = require("fs")
const path = require("path")
const port = process.env.PORT || 4000
http.createServer((req, res) => {
    switch (req.method) {
        // serve get requests
        case "GET": 
            // this is a request to the home page, return index.html
            if (req.url === '/') {
                fs.createReadStream(path.join(__dirname + 'index.html')).pipe(res)
            }
           // call the function that serves static files, passing req, and res parameters
            serveStaticFiles(req, res)
            break;
        // serve post requests
        case "POST":
            if (req.url === '/postrequest') {
                req.on('data',  (chunk) => {
                    // you can access data sent via post i.e
                    let data = chunk.toString() // converting to string because Node receives data as a buffer
                    // do some processing and send back response
                    res.end(JSON.stringify({ 'message' : 'data received and processed' }));
                });
            }
            break;
        default:
            // you can have an error page if requests don't match above
            fs.createReadStream(path.join(__dirname + '/error.html')).pipe(res);
            break;
    }
}).listen(port, () => console.log(`Server listening at port: ${port}`))

// function to serve static files, js, css, images and the likes
function serveStaticFiles(req, res) {
   // specifying root path e.g. 'public' in this case will only allow serving files within the public folder and disable directory listing of other files
    let rootPath = path.join('public' + req.url),
         mimeType = Object.create({
        '.js': 'text/javascript',
        '.css': 'text/css'
    })

    // check if file exists in public folder
    fs.existsSync(rootPath) ? (function () {
        // file found, return status 200 plus the file content
        fs.readFile(rootPath, (err, data) => {
            err ? (function () {
                res.writeHead(500, 'Internal server error', { 'Content-Type': 'text/plain' });
                res.end()
            })() : (function () {
                res.writeHead(200, { 'Content-Type': mimeType[path.extname(rootPath)] })
                res.end(data)
            })();
        });
    })() : (function () {
        // file not found and thus return 504
        res.writeHead(404, 'Ruquested file not found')
        res.end()
    })()
}