excludeCredentials causes an error if transports is not indicated

[gianluca-venturini]

Description

In the Debugger view it's not possible to set one element in excludeCredentials without indicating transports. According to the specs, transports should be optional. When I try to not add transports I see this error

TypeError: Failed to execute 'create' on 'CredentialsContainer': Failed to read the 'publicKey' property from 'CredentialCreationOptions': Failed to read the 'excludeCredentials' property from 'PublicKeyCredentialCreationOptions': The provided value is not of type 'PublicKeyCredentialDescriptor'.

while indicating one of the three transports methods everything works as expected.

Reproduction

• Open Debugger view
• Register a new device (e.g. Macbook Touch ID)
• Copy the rawId to a file (in binary format)
• Add one excludeCredentials element and upload binary file
• Try to register a second device
• Observe the failure
• Expected behavior: I can register a second device

Environment

• Version of this library used:
• Used web version of the tool deployed at https://webauthn.me/debugger, latest commit on master is 77679df
• Chrome Version 103.0.5060.53 (Official Build) (arm64)