Add hasInternetCredentials

[Jyrno42]

This checks if the username/password combination for server is available in the secure storage.
Resolves to true if an entry exists or false if it doesn't.

[vonovak]

hi @Jyrno42 and thanks for the PR. Can you explain the motivation for this? Specifically, how is this different from checking the result of getInternetCredentials? Thanks.

[Jyrno42]

The difference between this and getInternetCredentials is that it does not require biometric [1] unlocking to check if the credentials exist or not. With this I can for example dynamically show/hide Login with Fingerprint/TouchID/FaceID button based on the existance of the credentials.

On android theres no use for this until #148 is merged.

[1] On IOS below 9 it will still ask for credentials since kSecUseAuthenticationUIFail was added in 9.

[vonovak]

Okay, that sounds reasonable! The ios 9 note should be added to the docs as well I think..?

[oblador]

Thanks @Jyrno42!
@vonovak Think maybe it's time to bump min supported version to iOS 9? This the new min in React Native as of 0.56.