Fix Firebase error "auth/emulator-config-failed"

const app = initializeApp(config.firebase)
const auth = getAuth(app)
connectAuthEmulator(auth, 'http://localhost:9099', { disableWarnings: true })
// note: 9099 is the default port Firebase used for their authen emulator

Uncaught FirebaseError: Firebase: Error (auth/emulator-config-failed).

async function setupEmulators(auth) {
  const authUrl = 'http://localhost:9099'
  await fetch(authUrl)
  connectAuthEmulator(auth, 'http://localhost:9099', { disableWarnings: true })
  // why? to make sure that emulator are loaded
}

const app = initializeApp(config.firebase)
const auth = getAuth(app)
setupEmulators(auth)