Simple web server with node.js

server.js

const http = require('http');
const path = require('path');
const fs = require('fs');

const port = 8080;

const server = http.createServer((req, resp) => {
    const filePathPart = req.url.substr(1) || 'index.html';
    const filePath = path.resolve(__dirname, filePathPart);
    if (!filePath.startsWith(__dirname)) {
        resp.writeHead(403);
        resp.end('Forbidden');
        return;
    }
    if (!fs.existsSync(filePath)) {
        resp.writeHead(404);
        resp.end('Not found');
        return;
    }
    const data = fs.readFileSync(filePath, 'utf8');
    resp.writeHead(200, 'OK', {
        'Content-Type': getContentType(path.extname(filePath)),
        'Cache-Control': 'no-cache, no-store, must-revalidate',
        Pragma: 'no-cache',
        Expires: '0'
    });
    resp.end(data);
});

server.listen(port, err => {
    if (err) {
        return console.error('Error', err);
    }
    console.log(`The server is running: http://127.0.0.1:${port}`);
});

function getContentType(ext) {
    switch (ext) {
        case '.html':
            return 'text/html';
        case '.js':
            return 'text/javascript';
        case '.css':
            return 'text/css';
    }
}