Currently you are not able to use auth module without a service account

Reproduction

vuefire/packages/nuxt/src/runtime/auth/plugin-authenticate-user.server.ts

Line 20 in 687ce09

const adminAuth = getAdminAuth(firebaseAdminApp)

Steps to reproduce the bug

Enable auth module

  vuefire: {
    auth: {
      enabled: true,
    },
    ...
  }

Make sure you don't have the GOOGLE_APPLICATION_CREDENTIALS set
Run npm run dev or build for production

Expected behavior

You should be allowed to use auth module without a service account

Actual behavior

You get this error when using the auth module without a service account specified.

The default Firebase app does not exist. Make sure you call initializeApp() before using any of the Firebase services

I think the problem comes from here

vuefire/packages/nuxt/src/runtime/auth/plugin-authenticate-user.server.ts

Line 20 in 687ce09

const adminAuth = getAdminAuth(firebaseAdminApp)

the getAdminAuth() is always called regardless of the fact you may not have a service account.

If you move the const adminAuth = getAdminAuth(firebaseAdminApp) inside the if block if (auth.currentUser?.uid !== uid) the problem goes away, or maybe it should be here

vuefire/packages/nuxt/src/module.ts

Line 203 in 687ce09

addPlugin(resolve(runtimeDir, 'auth/plugin-authenticate-user.server'))

to add a if block if (nuxt.options.ssr && hasServiceAccount)

Additional information

Our use case is that, we don't have a service account because we don't need to render anything on the server based on authentication state, we are only using authentication on client side in some <client-only /> components