The auth emulator seems to always generate a token where auth_time is null. This causes the auth emulator to throw "auth/internal-error" when calling getIdTokenResult.

This is most likely the bug causing #3671 and #3663

[REQUIRED] Environment info

firebase-tools: 9.16.1, 9.16.2, 9.16.3

Platform: Windows

[REQUIRED] Test case

Try calling getIdTokenResult in a client app that is connected to the latest version of firebase-tools's auth emulator. Notice the error that is thrown.

[REQUIRED] Steps to reproduce

1. Run npm run serve using firebase-tools 9.16.3
2. Run a client application that connects to the firebase auth emulator
3. Signup a new user
4. Call getIdTokenResult on that new user

[REQUIRED] Expected behavior

You are able to decode the user's token and retrieve their claims.

[REQUIRED] Actual behavior

"auth/internal-error" is thrown

If you breakpoint the line of code where "auth/internal-error" is thrown, you'll see that the error is thrown because auth_time is null in the decoded token.

@yuchenshi This bug may possibly have something to do with the PR I submitted a few weeks ago. Perhaps lastLoginAt is undefined?

#3611

If so, perhaps try changing these lines of code

to

    auth_time:
      user.lastLoginAt != null && user.lastLoginAt != undefined
        ? toUnixTimestamp(new Date(user.lastLoginAt))
        : user.lastRefreshAt != null && user.lastRefreshAt != undefined
        ? toUnixTimestamp(new Date(user.lastRefreshAt))
        : toUnixTimestamp(new Date()),