Restart an Express.js server with the same port

Question

I have a Node.js app that uses Express.js to listen for connections. The code is something like so:

const express = require("express");
var server = express();
server.get("/test", (req, res) => testResponse(req, res));
server.listen(9001);
console.info("Server is listening to port 9001.");

I'd like to implement a way to restart the server without having to restart the whole app. However, I can't seem to properly shut down the server and free the port. Here's what I tried:

server.close();
console.info("Server closed. Restarting.");

var server = express();
server.get("/test", (req, res) => testResponse(req, res));
server.listen(9001);
console.info("Server is listening to port 9001.");

As soon as I run this, I get

Error: listen EADDRINUSE :::9001

What would be the correct way to do this?

Cheers.

Answer 1

server.close() is asynchronous and takes a callback. Try waiting until the server is actually closed before starting a new one:

server.close(()=>{

    console.info("Server closed. Restarting.");

    var server = express();
    server.get("/test", (req, res) => testResponse(req, res));
    server.listen(9001);
    console.info("Server is listening to port 9001.");

});