Launch at another port if the current is taken

[todortotev]

Excuse me if I'm missing something, but is it possible to have a command-line option if the port is taken? Seen it @ other apps so I thought it would come in handy.

For example, if port 3000 is taken, you get a message - Port XXXX is taken, do you want to use another port? Y/n

Currently, if the port is taken you get an error which also is okay, but I guess it would be even better if you can just click Y and get the app launched at a different port.

[Vadorequest]

Next.js automatically uses the next available port already.

If 3000 is taken, it tries 3001 and so on, until one free port is found.

[todortotev]

☘️

[kkhcheng]

is there a way to go back to the old behavior? that seems more convenient in som cases

[eXamadeus]

Yeah, for those tuning in in 2023, Next.js now automatically grabs the next available port, for some reason.

Personally not a fan of automatically picking a port. I want to KNOW if there's an orphaned instance running. Why was this change made? I can't fathom a good reason for having a randomly assigned port. Sorry if I'm resurrecting a dead thread, but seems like Next.js was onboard with this for a while. I'd be interested to know the reasoning behind the change.

If the goal is to satisfy everyone, I feel like the automatic port selection can be left as the default, but turn it off when a port is specified. If I run next dev -p 3000 and port 3000 is taken, I'd rather see an error than just randomly have Next.js popup at port 3001.

[dbrxnds]

Completely agree @eXamadeus. We just ran into this issue with production builds suddenly using another port than we assigned. How are we supposed to have it error on us?

[Kuroashi1995]

Does somebody knows if it at least exports the port where it's running so I can dynamically set a variable that I need?