index.ts

import App from './app';

const server = App.server;
const port = App.port;

server.on('error', onError);
server.on('listening', onListening);

function onError(error: NodeJS.ErrnoException): void {
    if (error.syscall !== 'listen') throw error;
    let bind = (typeof port === 'string') ? 'Pipe ' + port : 'Port ' + port;
    switch (error.code) {
        case 'EACCES':
            console.error(`${bind} requires elevated privileges`);
            process.exit(1);
            break;
        case 'EADDRINUSE':
            console.error(`${bind} is already in use`);
            process.exit(1);
            break;
        default:
            throw error;
    }
}

function onListening(): void {
    let addr = server.address();
    let bind = (typeof addr === 'string') ? `pipe ${addr}` : `port ${addr.port}`;
    console.log(`Listening on ${bind}`);
}