userPool.getCurrentUser().username returns alias instead of username for custom auth

[SNagappan]

I experienced the exact same bug on the iOS SDK which I filed here: https://github.com/aws-amplify/aws-sdk-ios/issues/3194

Workflow: I implemented custom auth using use case #25 located here: https://github.com/aws-amplify/amplify-js/tree/master/packages/amazon-cognito-identity-js. On the backend, authentication is done through the define/create/verify lambda triggers in cognito. The registration of new users is all done on the server side with admin create user, set password, and linking 3rd party provider accounts.

Problem: When I sign in using cognitoUser.initiateAuth() using an alias, userPool.getCurrentUser().username returns the alias instead of the username. For example, if i signed in with an email alias, userPool.getCurrentUser().username would return the email of the user instead of the actual username. My expectation is that it would always return the username.

[harrysolovay]

This is the expected behavior: when logging in, the username is the supplied unique reference to the user. This can be email address, phone number, or an explicitly-defined username.

If this behavior is undesirable, I'd recommend creating a function which calls userPool.getCurrentUser() and––from its response––distinguishes between and returns the desired username type (for instance, assessing whether the string contains email-only-chars (username.includes("@"))).

[SNagappan]

@harrysolovay When I sign in with an email alias using the standard username/password method, the returned username is actual username and not the email. I'd argue that there is an issue here - standard auth and custom auth are working inconsistently.

[harrysolovay]

Please confirm this is the issue you're having: you're unable to get a consistent reference to the username and email when logging in with different methods?

[SNagappan]

Yes, that is correct. I am unable to get a consistent reference for username with standard and custom auth.