Simple error processing

lib/microsoft_translator/client.ex

@@ -69,29 +69,34 @@ defmodule MicrosoftTranslator.Client do
 
   defp parse(%{body: body}, api_method) do
     Jason.decode!(body, keys: :atoms)
-    |> transform_response(api_method)
+    |> process_response(api_method)
   end
 
-  defp transform_response(response, :detect) do
-    result =
-      response
-      |> List.first()
-      |> Map.fetch(:language)
+  defp process_response(response, api_method) do
+    case response do
+      %{error: %{code: code, message: message}} ->
+        %{error: %{code: code, message: message}}
 
-    case result do
+      list when is_list(list) and api_method in ~w(detect translate)a ->
+        list
+        |> List.first()
+        |> transform_response(api_method)
+
+      map when is_map(map) and api_method in ~w(languages)a ->
+        transform_response(map, api_method)
+    end
+  end
+
+  defp transform_response(response, :detect) when is_map(response) do
+    case Map.fetch(response, :language) do
       {:ok, language} -> %{languageCode: language}
     end
   end
 
-  defp transform_response(response, :translate) do
-    response
-    |> List.first()
-    |> Map.take([:translations])
-  end
-
-  defp transform_response(response, :languages) do
-    %{dictionary: dictionary} = response
+  defp transform_response(response, :translate) when is_map(response),
+    do: Map.take(response, ~w(translations)a)
 
+  defp transform_response(%{dictionary: dictionary}, :languages) do
     dictionary
     |> Enum.map(fn {key, %{name: name, nativeName: native, dir: dir}} ->
       %{code: "#{key}", name: name, nativeName: native, dir: dir}