Fibonacci Number Generator in Elixir

fib.exs

defmodule Fib do
  def number(n) do
    cache =
    2..n
    |> Enum.reduce(%{prev: 0, current: 1}, fn _i, acc ->
      %{prev: acc.current, current: acc.prev + acc.current}
    end)
    |> Map.get(:current)
  end
end

Fib.number(5)