Add user-friendly error message when localhost port is already taken

[cinnamon-bun]

What's the problem you want solved?
If the port is already taken by Oasis or some other process, you get this error:

  oasis Listening on http://localhost:3000/ +0ms
events.js:200
      throw er; // Unhandled 'error' event
      ^

Error: listen EADDRINUSE: address already in use 127.0.0.1:3000
    at Server.setupListenHandle [as _listen2] (net.js:1306:16)
    at listenInCluster (net.js:1354:12)
    at GetAddrInfoReqWrap.doListen [as callback] (net.js:1493:7)
    at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:65:10)
Emitted 'error' event on Server instance at:
    at emitErrorNT (net.js:1333:8)
    at processTicksAndRejections (internal/process/task_queues.js:81:21) {
  code: 'EADDRINUSE',
  errno: 'EADDRINUSE',
  syscall: 'listen',
  address: '127.0.0.1',
  port: 3000
}

Is there a solution you'd like to recommend?
Show a more friendly message like

Error: another server is already running at http://localhost:3000.
It might be another copy of Oasis or another program on your computer.
You can run Oasis on a different port number with this option:
    oasis --port 3001

[christianbundy]

Yes! This would be rad, and probably super simple. We'd just need to wrap the http.listen() in a try {} catch(e) {} and as long as e.code (or e.type?) is "EADDRINUSE" we can show this error instead of the stacktrace.

[christianbundy]

Just tried the above method and it didn't work. Looks like there are some shenanigans afoot.