firebase emulators:start Fails with ESM Import Error in Emulator UI on MacOS

[scottnimos]

Describe the bug

Running firebase emulators:start --debug causes a fatal error in the Emulator UI, exiting with code 1. This error appears to be related to the module type for server.mjs, which requires ESM support but is being handled by CommonJS’s require().

To Reproduce

1. Run firebase init and select only auth to emulate.
2. Enable the Emulator UI during setup.
3. Execute firebase emulators:start.

My firebase.json

{
  "emulators": {
    "auth": {
      "port": 9099
    },
    "ui": {
      "enabled": true
    },
    "singleProjectMode": true
  }
}

Expected behavior

The emulators should start successfully, with the Emulator UI accessible and logging as expected.

Screenshots

No screenshots were provided.

Desktop (please complete the following information):

• OS: MacOS 15.0.1 (24A348)
• Browser: (e.g., Chrome, Safari)
• Version: (e.g., Chrome 22)

Additional context

• Node version: v20.14.0
• The error suggests using import() in place of require() for /server/server.mjs, aligning with Node's ESM requirements.
• Emulator UI version: v1.14.0