title: Handling form erros under ngrx & ngrx/effects
body: <p>I'm trying to design an auth mechanism under ngrx but I've yet to wrap my head around ngrx.</p>
  
  <p>The authentication works like this: client inputs his email and password, a request to /api/auth is made with his credentials, if the credentials aren't correct we receive an error and an error message is seen on the login form. If the credentials are correct we receive the user object and we redirect the user to the home page.</p>
  
  <p>Here is how I see it</p>
  
  <p><a href="https://i.stack.imgur.com/cxa4L.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cxa4L.jpg" alt="enter image description here"></a></p>
  
  <p>So the part I'm struggling with is the when <code>@Effect</code> receives the response. </p>
  
  <p>I assume that in my store I have an <code>userReducer</code> that contains the state of the user. When the response from <code>api/auth</code> is the user then an action <code>SET_USER</code> is dispatched to the reducer to set the user. However I'm not sure what to do with the error message.</p>
  
  <ul>
  <li>Do I need to have a reducer for the form as well ? </li>
  <li>Do I need a reducer for each form ? Seems to me error message isn't part of the long lived state of an app. It's just something that should be displayed then forgotten.</li>
  <li>How do I redirect on login success ?</li>
  </ul>