@mikkel-ol/tunnelmole/src/message-handlers/hostname-already-taken.ts

Tunnelmole, an open source ngrok alternative. Instant public URLs for any http/https based application. Available as a command line application or as an NPM dependency for your code. Stable and maintained. Good test coverage. Works behind firewalls

export default async function hostnameAlreadyTaken(message: any) {
  console.error(
    message.hostname + " is already taken, please choose a different hostname",
  );
  process.exit(0);
}