Node + Express bin/www with TypeScript

www.ts

#!/usr/bin/env node

import debugFactory from "debug";
import http from "http";
import app from "./../app";
const debug = debugFactory(process.env.DEBUG);

/**
 * Get port from environment and store in Express
 */
const port = normalizePort(process.env.PORT);
app.set("port", port);

/**
 * Create a HTTP server
 */
const server = http.createServer(app);

/**
 * Listen on provided port, on all network interfaces
 */
server.listen(port);
server.on("error", onError);
server.on("listening", onListening);

/**
 * Normalize a port into a number, string or false
 *
 * @param {any} value
 * @return {number|string|false}
 */
function normalizePort(value: any): number|string|false {
    const port = parseInt(value, 10);

    // Named pipe
    if (isNaN(port)) {
        return value;
    }

    // Port number
    if (port >= 0) {
        return port;
    }

    return false;
}

/**
 * Event listener for HTTP server "error" event
 *
 * @param {any} error
 */
function onError(error: any): void {
    if (error.syscall !== "listen") {
        throw error;
    }

    const bind = typeof port === "string" ? `Pipe ${port}` : `Port ${port}`;

    // Handle specific listen errors with friendly messages
    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;
    }
}

/**
 * Event listener for HTTP server "listening" event
 */
function onListening(): void {
    const address = server.address();
    const bind = typeof address === "string" ? `pipe ${address}` : `port ${address.port}`;

    debug(`Listening on ${bind}`);
}