Sign-in button capabilities like in Googles Demo

[BananaAcid]

Describe the issue

I try to implement a sign-in button like on Google's Passkey Demo

• after working through the example and reading the docs, I am not able to spot any Info about it -- It looks to me like this project is only for protecting a successful login with a 2FA by passkeys.

Is my conclusion actually correct ?

Documentation

An info in the Readme.md about this being possible or not would be great.

Additional context

The example's code for route "/generate-authentication-options" it states "You need to know the user by this point" index.ts#L221-L222

Same for the "/verify-authentication" route.

... for me, the purpose using sign-in with passkeys is, not having the user logged in by that point ;)

[MasterKale]

There's a couple sections in the docs that might help shed some light on how to pull off an experience like the one on Google's demo site:

• Advanced Guides > Passkeys > generateAuthenticationOptions(): https://simplewebauthn.dev/docs/advanced/passkeys#generateauthenticationoptions
• Packages > @simplewebauthn/browser > startAuthentication() > Browser autofill, a.k.a. Conditional UI: https://simplewebauthn.dev/docs/packages/browser#browser-autofill-aka-conditional-ui

Take a look at those and let me know if that helps shed some light on this.

tl;dr: Make sure allowCredentials is an empty array before options make it to navigator.credentials.get(), either manually when calling generateAuthenticationOptions() or by calling startAuthentication(..., true) when using conditional UI.