Search where is located a key-value pair in deeply nested structs

find_path.ex

defmodule MapUtils do
   def find_pair_path(map, key, value) when is_map(map) do
    do_find_pair_path(map, key, value, [])
    |> Enum.map(&(&1 |> List.flatten() |> Enum.reverse()))
    |> Enum.reject(&(&1 == nil || &1 == []))
  end

  defp do_find_pair_path(map, key, value, path) when is_map(map) do
    keys = Map.keys(map)

    if key in keys and Map.get(map, key) == value do
      [key | path]
    else
      Enum.map(keys, fn subkey ->
        Map.get(map, subkey)
        |> do_find_pair_path(key, value, [subkey | path])
      end)
    end
  end

  defp do_find_pair_path(list, key, value, path) when is_list(list) do
    Enum.with_index(list)
    |> Enum.map(fn {elem, index} ->
      do_find_pair_path(elem, key, value, [{:at, index} | path])
    end)
  end

  defp do_find_pair_path(_, _, _, _), do: []
end

# [[:a, :b, "name"]]
%{a: %{b: %{"name" => "ivan"}}} |> MapUtils.find_pair_path("name", "ivan")
# [[:a, :b, {:at, 0}, "name"]]
%{a: %{b: [%{"name" => "ivan"}]}} |> MapUtils.find_pair_path("name", "ivan")
# [[:a, {:at, 0}, :b, {:at, 0}, "name"]]
%{a: [%{b: [%{"name" => "ivan"}]}]} |> MapUtils.find_pair_path("name", "ivan")