.then(user => {
        logger.debug('signIn success');
        if (!user.challengeName) {
          authState.next({ state: 'signedIn', user: user });
          return user;
        }

        logger.debug('signIn challenge: ' + user.challengeName);
        if (user.challengeName === 'NEW_PASSWORD_REQUIRED') {
          authState.next({ state: 'requireNewPassword', user: user });
        } else if (user.challengeName === 'MFA_SETUP') {
          authState.next({ state: 'setupMFA', user: user });
        } else if (
          user.challengeName === 'SMS_MFA' ||
          user.challengeName === 'SOFTWARE_TOKEN_MFA'
        ) {
          authState.next({ state: 'confirmSignIn', user: user });
        } else {
          logger.debug('warning: unhandled challengeName ' + user.challengeName);
        }
        return user;
      })

 .catch(err => {
   logger.debug('signUp error', err);
   throw err;
 });