Error: listen EADDRINUSE: address already in use :::5000

• nodemon -v: 2.0.7
• node -v: 14.16.01
• Operating system/terminal environment: MacOS Big Sur
• Using Docker? No
• Command you ran: nodemon server

Expected behaviour

Close port before reinitializing server.

Actual behaviour

[0] [nodemon] starting `node server.js`
[0] events.js:292
[0]       throw er; // Unhandled 'error' event
[0]       ^
[0] 
[0] Error: listen EADDRINUSE: address already in use :::5000
[0]     at Server.setupListenHandle [as _listen2] (net.js:1318:16)
[0]     at listenInCluster (net.js:1366:12)
[0]     at Server.listen (net.js:1452:7)
[0]     at Function.listen (/Users/tf/Documents/courses/MERN/server/node_modules/express/lib/application.js:618:24)
[0]     at Object.<anonymous> (/Users/tf/Documents/courses/MERN/server/server.js:35:5)
[0]     at Module._compile (internal/modules/cjs/loader.js:1063:30)
[0]     at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
[0]     at Module.load (internal/modules/cjs/loader.js:928:32)
[0]     at Function.Module._load (internal/modules/cjs/loader.js:769:14)
[0]     at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)
[0]     at internal/main/run_main_module.js:17:47
[0] Emitted 'error' event on Server instance at:
[0]     at emitErrorNT (net.js:1345:8)
[0]     at processTicksAndRejections (internal/process/task_queues.js:80:21) {
  code: 'EADDRINUSE',
[0]   errno: -48,
[0]   syscall: 'listen',
[0]   address: '::',
[0]   port: 5000
[0] }
[0] [nodemon] app crashed - waiting for file changes before starting...

Steps to reproduce

1. Initialize app (basic MERN app)
2. Save any file.
3. Error is thrown.

This only started happening after I updated my Mac to Big Sur. I can circumvent this issue by either stopping the app and killing the port or by saving a second time a couple of seconds after the first crashed the server.

[roshennair]

I’ve found a temporary work-around, the steps for which are listed below:

1. Install the NPM kill-port package as a development dependency: npm install -D kill-port
2. Create a new file in your project’s root directory called nodemon.json and paste in the following JSON (edit the port numbers below from 3000 to whatever port you’re using for your Node.js app):

{
	"events": {
		"restart": "kill-port 3000",
		"crash": "kill-port 3000"
	 },
	"delay": "1500"
}

1. Add the following NPM script to your package.json file (if you haven’t already):

"scripts": {
	"dev": "nodemon app.js",
},

All credit goes to Tudor Constantin on Stack Overflow. However, it is a bit tedious and definitely a workaround, not something that should be done for all future Node.js projects.

[remy]

Okay, start striping the code back until you have the bare minimum and you can still replicate, then post that here, then we can take a look.