Firebase UI is incompatible with Firebase SDK 9 (beta)

• Firebase UI version: 4.8.0
• Firebase SDK version: 0.900.19

Firebase SDK 9 is now released in beta. When testing with Firebase UI 4.8.0, it becomes clear that Firebase UI is not ready to be used with the modularized import api of Firebase SDK 9.

Steps to reproduce:

1. Load Firebase UI with Firebase SDK 9:

import { getApp } from 'firebase/app'
import { getAuth }  from 'firebase/auth'
import * as firebaseui from 'firebaseui';

const app = getApp();
const auth = getAuth(app);
uiConfig = (…)
new firebaseui.auth.AuthUI(auth).start('#firebaseui-auth-container', uiConfig);

1. Experience TypeError, since firebase is undefined in firebaseui-web: https://github.com/firebase/firebaseui-web/blob/1a8f9e523f76df7a6c5da36b63b4d2a5b34b64ef/javascript/widgets/authui.js#L127

TypeError: Cannot read property 'initializeApp' of undefined

@davideast has commented on the issue over at https://github.com/firebase/firebase-js-sdk/discussions/4375#discussioncomment-330765 in February:

We don't have a version of Firebase UI available for the new SDK just yet. But hang tight!

I could not see the issue being tracked here, so therefore I’m posting it as a specific reproducible bug to track. (The theme is somewhat already addressed in #257, however there as a more general issue).

[jamesdaniels]

Working on support over at #850 FYI.

[shauryaaher]

Hi @shauryaaher, for now FirebaseUI-web only works with v9 via the compatibility layer. We know this is a pain point, and we’re investigating updates to allow it to work with the modular syntax, but at this time I can’t share any timelines.

Ok. Let’s hope it comes around soon. I would be really good if it comes around a week after Google IO. I’m terrible at CSS styling, and I don’t have a very big team to handle that work for me.