const express = require('express'); var app = express(); app.use(express.static('root')); const port = !process.argv[2] ? 3000 : Number.isInteger(Number(process.argv[2])) ? Number(process.argv[2]) : 3000 app.listen( port, (err) => { if (err) throw err; else { console.log(`Successful runned 127.0.0.1:${port}`); } } );