Reducing Reducers - Elixir

mapper.exs

defmodule Mapper do
  def extract_associations(%{} = game) do
    Enum.reduce(map, %{}, fn {key, value}, item ->
      cond do
        is_map(value) ->
          put_map(item, key, extract_map_data(value))

        is_list(value) ->
          list_data = Enum.reduce(value, [], &[extract_map_data(&1) | &2])
          put_map(item, key, list_data)

        true ->
          put_map(item, key, value)
      end
    end)
  end

  defp extract_map_data(map), do: Enum.reduce(map, %{}, fn {k, v}, acc -> put_map(acc, k, v) end

  defp put_map(map, key, value), do: Map.put(map, String.to_existing_atom(key), value)
end