text: const app = require("./app");
  
  const PORT = process.env.PORT || 3001;
  
  // Why don't I need http createServer
  app.listen(PORT, () => {
    console.log(`App listening on port ${PORT}!`);
  });
  app.on("error", onError);
  
  function onError(error) {
    if (error.syscall !== "listen") {
      throw error;
    }
  
    var 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);
        break;
      case "EADDRINUSE":
        console.error(bind + " is already in use");
        process.exit(1);
        break;
      default:
        throw error;
    }
  }
  