server.js

#!/usr/bin/env node

/**
 * @file_brief -> This file specifies error handlers, and mounts the express app on a node.js server (exported from ${REPO_ROOT}/app.js)
 */
 const app = require("./app");
 const { exit } = require("process");
 
 const PORT = process.env.PORT || "8080";
 app.set("port", PORT);
 
 /**
  * @brief - Event listener for HTTP server "error" event.
  * 
  * @param - `error` is the error object
  * @returns process.exit call
  */
 function onError (error) {
     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");
         return process.exit(1);
     case "EADDRINUSE":
         console.error(bind + " is already in use");
         return process.exit(1);
     default:
         throw error;
     }
 }
 
 function onListening () {
    //  const addr = server.address();
    //  const bind = typeof addr === "string"
    //      ? "pipe " + addr
    //      : "port " + addr.port;
     console.log("Listening on " + PORT);
 }
 
 function exitHandler(sig) {
     console.log(`Recieved ${sig}: Exiting gracefully`);
     server.close((err) => {
         console.log("Couldn't close server, due to ",err);
     });
     exit(0);
 }
 
 process.on("SIGTERM", exitHandler);
 process.on("SIGINT", exitHandler);
 
 app.on("error", onError);
 const server = app.listen(PORT, onListening);