less_naive_2.ex

defmodule LessNaive do
  def trim_string(string) do
    string
    |> String.graphemes()
    |> Enum.reduce_while({0, ""}, fn grapheme, {count, acc} ->
      count = count + counter(grapheme)

      if count <= 80,
        do: {:cont, {count, acc <> grapheme}},
        else: {:halt, acc}
    end)
  end

  defp counter(string), do: string |> String.codepoints() |> Enum.count()
end