Prevent new domain request until new subdomain is correct.

src/App/DomainListInterface.purs

@@ -262,11 +262,13 @@ handleAction = case _ of
 
   HandleNewDomainInput adduserinp -> do
     case adduserinp of
-      INP_newdomain        v      -> do
+      INP_newdomain v -> do
         H.modify_ _ { newDomainForm { new_domain = v } }
-        case runParser v DomainParser.domain of
-          Left error_string -> H.modify_ _ { newDomainForm { error_string = Just $ show error_string } }
-          Right _           -> H.modify_ _ { newDomainForm { error_string = Nothing } }
+        case v of
+          "" -> H.modify_ _ { newDomainForm { error_string = Nothing } }
+          otherwise -> case runParser v DomainParser.domain of
+            Left error_string -> H.modify_ _ { newDomainForm { error_string = Just $ show error_string } }
+            Right _           -> H.modify_ _ { newDomainForm { error_string = Nothing } }
       UpdateSelectedDomain domain -> H.modify_ _ { newDomainForm { selected_domain = domain } }
 
   EnterDomain domain -> do
@@ -287,10 +289,12 @@ handleAction = case _ of
     { newDomainForm } <- H.get
     let new_domain = build_new_domain newDomainForm.new_domain newDomainForm.selected_domain
 
-    case new_domain of
-      "" ->
+    case newDomainForm.error_string, new_domain of
+      Just error_string, _ ->
+        H.raise $ Log $ UnableToSend $ "You didn't enter a valid new domain: " <> error_string
+      _, "" ->
         H.raise $ Log $ UnableToSend "You didn't enter the new domain!"
-      _ -> do
+      Nothing, _ -> do
         message <- H.liftEffect
           $ DNSManager.serialize
           $ DNSManager.MkNewDomain { domain: new_domain }