Externalize error messages

modules/webapp/src/main/elm/Page/Queue/Data.elm

@@ -1,5 +1,6 @@
 module Page.Queue.Data exposing
-    ( Model
+    ( FormState(..)
+    , Model
     , Msg(..)
     , QueueView(..)
     , emptyModel
@@ -20,7 +21,7 @@ import Util.Maybe
 
 type alias Model =
     { state : JobQueueState
-    , error : String
+    , formState : FormState
     , pollingInterval : Float
     , init : Bool
     , stopRefresh : Bool
@@ -32,6 +33,11 @@ type alias Model =
     }
 
 
+type FormState
+    = InitialForm
+    | HttpError Http.Error
+
+
 type QueueView
     = CurrentJobs
     | QueueAll
@@ -44,7 +50,7 @@ type QueueView
 emptyModel : Model
 emptyModel =
     { state = Api.Model.JobQueueState.empty
-    , error = ""
+    , formState = InitialForm
     , pollingInterval = 1200
     , init = False
     , stopRefresh = False