resistor-color-duo

elixir/resistor-color-duo/lib/resistor_color_duo.ex

@@ -0,0 +1,25 @@
+defmodule ResistorColorDuo do
+  @doc """
+  Calculate a resistance value from two colors
+  """
+  @spec value(colors :: [atom]) :: integer
+  def value(colors) do
+    colors
+    |> Enum.take(2)
+    |> Enum.map(&code/1)
+    |> Integer.undigits()
+  end
+
+
+  @spec code(atom) :: integer()
+  defp code(:black), do: 0
+  defp code(:brown), do: 1
+  defp code(:red), do: 2
+  defp code(:orange), do: 3
+  defp code(:yellow), do: 4
+  defp code(:green), do: 5
+  defp code(:blue), do: 6
+  defp code(:violet), do: 7
+  defp code(:grey), do: 8
+  defp code(:white), do: 9
+end