Ideally, the next step would be to add a proper login form to the currently not implemented-yet LoginComponent, which has been around as an empty skeleton since Chapter 3, Frontend with Angular. However, before doing that, we need to provide our Angular SPA with a TokenResponse interface--to handle the TokenResponseViewModel in a strongly-typed fashion--and an AuthService class where we will centralize all the auth-related methods, such as login, logout, and isLoggedIn.