const http = require("http"); const HOSTNAME = process.env.HOSTNAME || "localhost"; const PORT = process.env.PORT || 3000; const server = http.createServer((request, response) => { response.statusCode = 200; response.setHeader("Content-Type", "text/plain"); response.end("Hello World"); }); server.listen(PORT, HOSTNAME, () => { console.log(`Server running at http://${HOSTNAME}:${PORT}/`); });