unable to run server, I think it is because I have 2 applications using the same port? - express

Question

Just Curious (I solved this problem by just using a different port but the issue still triggers me), When I am trying to run the following code:
const app = express();
app.use(bodyParser.json({ limit: "30mb", exteded: true }));
app.use(bodyParser.urlencoded({ limit: "30mb", extended: true }));
app.use(cors());
const CONNECTION_URL = <correct MongoDB connection url>
const PORT = process.env.PORT || 5000;
mongoose.connect(CONNECTION_URL, { useNewUrlParser: true, useUnifiedTopology: true })
.then(() =>
app.listen(PORT, () => console.log(`Server running on port`+PORT))
).catch((error) => console.log(error.message));
I keep getting an error thrown in my console:
{ code: 'EADDRINUSE', errno: -48, syscall: 'listen', address: '::', port: 5000 }
so after surfing through countless numbers of resources, they all essentially said I had to applications using the same port 5000? So I followed the "solutions" to the problem which all seemed to be killing the Port.
Firstly, I ran:
netstat -avtn | egrep 'Proto|5000'
To get:
Foreign Address (state) rhiwat shiwat pid epid state options
tcp6 0 0 *.5000 *.* LISTEN 131072 131072 1883 0 0x0100 0x00000006
tcp4 0 0 *.5000 *.* LISTEN 131072 131072 1883 0 0x0100 0x00000006
then I tried a few different commands to try and kill.
1) kill -9 $(lsof -t -i:5000)
2) kill <the appropriate pid>
3) kill -9 <the appropriate pid>
However, none of the solutions seemed to work. I even tried the famous computer off and on solution and closed all my applictions but they didn't work either. Does anyone know how I could have solved this without changing my port number?

Answer 1

Two different applications/processes cannot run on the same port. You will need to use different ports to use them parallelly.
Based on your OS there are tons of resources online to kill a process running on a specific port. The process/commands are similar to the ones you have listed to kill a process on a port.