Passkeys - JSON.stringify() fallback for various password managers

[maartenba]

Passkeys - JSON.stringify() fallback for various password managers

Some password managers do not implement PublicKeyCredential.prototype.toJSON correctly, which is required for JSON.stringify() to work when serializing a passkey credential - e.g. https://www.1password.community/discussions/1password/typeerror-illegal-invocation-in-chrome-browser/47399

This PR adds a fallback to work with various password managers.

• Issue: Passkeys - Illegal invocation with 1Password #62916
• Note the helper function to convert to base64 is from @abergs helper functions at https://github.com/passwordless-lib/fido2-net-lib/blob/master/Demo/wwwroot/js/helpers.js (MIT License, suggestions on how to communicate this in the PR are welcome)

[dotnet-policy-service]

Thanks for your PR, @@maartenba. Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[Copilot]

Pull Request Overview

This PR adds a fallback mechanism for JSON serialization of passkey credentials to handle password managers that don't properly implement PublicKeyCredential.prototype.toJSON. The change addresses compatibility issues where JSON.stringify() fails with an "Illegal invocation" error in certain password managers like 1Password.

• Wraps the existing JSON.stringify(credential) call in a try-catch block
• Implements manual JSON serialization as a fallback when the standard approach fails
• Adds a helper function to convert ArrayBuffer/Uint8Array data to base64url format

[abergs]

Since I was pinged, for some long forgotten reason I rewrote the helpers here:
https://github.com/bitwarden/passwordless-client-js/blob/main/src/passwordless.ts#L439-L487 (Apache 2.0)