what I am trying to do, is to code an auth. with NextJS and Firebase.

Now the problem appears in my firebaseClient.js, where I get the error "TypeError: Cannot read properties of undefined (reading 'apps')".

The code looks like this:

import firebase from "firebase/app";

import "firebase/auth";
import "firebase/database";

const FIREBASE_CONFIG = {
  // config files from firebase here
};

export default function firebaseClient() {
  if (!firebase.apps.length) {
    firebase.initializeApp(FIREBASE_CONFIG);
  }
}

In the console I get this error: Terminal Error

This appears on the localhost:3000: Error Page on localhost:3000

I am following this YT tutorial here , which is from 2020, so some imports, as far as I can tell, changed.