flat_array.rb

require "minitest/autorun"


module ArrayTools
  refine Array do
    def flatt
      reduce([]) do |new_array, el|
        if el.instance_of? Array
          new_array += el.flatt
        else
          new_array << el
        end
      end
    end
  end
end


class TestArrayTools < Minitest::Test
  using ArrayTools

  def test_flatt
    assert_equal [1,2,3,4], [[[1,2,[3]],4]].flatt
  end
end