index.js reading the asynchronous way

index.js

const server = http.createServer((req, res) => {

    const URL = req.url;
    if (req.url === '/') {
        
        // We try to read the method in a Synchronous way
        // Note that we dont assign the output to a variable,
        // instead, we store the output in the second parameter of the
        // callback function.
        fs.readFile('./views/index.html', (err, data) => {
            //  A little bit of error handling
            if (err) {
                res.writeHead(404);
                res.write('file not found');
                throw err;
            } else {
            //  We Write the headers  
                res.writeHead(200, {
                    'Content-Length': data.length,
                    'Content-Type': 'text/html',
                });
            //  We send the using the second argument in the callback function
                console.log(data);
                res.write(data);
                res.end();
            }
        });

    }
}).listen(PORT);