How we can manage without server key while calling firebase apis

Describe the bug

In Auth.js, import firebase/auth.
import { onAuthStateChanged, getAuth } from 'firebase/auth'

define const auth. pass app imported from base.js into getAuth()
const auth = getAuth(app)

Next, in the useEffect, remove app.auth(). pass auth as first parameter in onAuthStateChanged.
onAuthStateChanged(auth, (user) => { setCurrentUser(user) setPending(false) });

!!REFERENCE!!
https://firebase.google.com/docs/auth/web/start
https://firebase.google.com/docs/auth/web/phone-auth

I implemented this into my application but it seems that the code to detect if currentUser exists

        !!currentUser ? (
          <RouteComponent {...routeProps} />
        ) : (
          <Redirect to={"/login"} />
        )

is executed before loading the currentUser

  useEffect(() => {
    app.auth().onAuthStateChanged(setCurrentUser);
  }, []);

so the result is the user will be redirected to login after refreshing the page.

Hi, can you let me know how to sign user out after creating user with email?. I want the user to verify his email before using the app.
I used auth().signOut() but it isn't working.

I tried running the app and it keeps throwing a 'default.auth() is not a function' error. Please can you help with this?

Module not found: Can't resolve 'firebase/app' in 'C:\Users\Utilisateur\Documents\react\learning-center-react\src'
How to resolve it please?