Monkey patch Array#flatten

flatten.rb

class Array
  def flatten
    @result = []
    _flatten(self)
  end

  private

  def _flatten(collection)
    collection.each do |item|
      if item.is_a? Array
        _flatten(item)
      else
        @result << item
        next
      end
    end
    @result
  end
end


p [1,2,3, [4,5], [[[6,7]]]].flatten