server.js

const http = require('http');
const app = require('./engine/start');
require('dotenv').config();

function normalizePort(val) {
    const port = parseInt(val, 10);

    if (isNaN(port)) {
        // named pipe
        return val;
    }
    if (port >= 0) {
        // port number
        return port;
    }
    return false;
}

const port = normalizePort( process.env.PORT || '8000');

function errorHandler(error) {
    if (error.syscall !== 'listen') {
        throw error;
    }
    const address = server.address();
    const bind = typeof address === 'string' ? 'pipe ' + address : 'port ' + port;
    switch (error.code) {
        case 'EACCES':
            console.error(`${bind} requires elevated privileges`);
            process.exit(1);
        case 'EADDRINUSE':
            console.error(`${bind} is already in use`);
            process.exit(1);
        default:
            throw error;
    }
}

const server = http.createServer(app);

server.on('error', errorHandler);
server.on('listening', () => {
    const address = server.address();
    const bind = typeof address === 'string' ? `pipe ${address}` : 'port ' + port;
    console.log(`Currently istening on ${bind}. Lessgo!`);
});

server.listen(port);