rails / ruby parameterize

parameterize.rb

class String
  def parameterize(separator: "-")
  # Turn unwanted chars into the separator.
      self.gsub!(/[^a-z0-9\-_]+/i, separator)

      unless separator.nil? || separator.empty?
        if separator == "-"
          re_duplicate_separator        = /-{2,}/
          re_leading_trailing_separator = /^-|-$/i
        else
          re_sep = Regexp.escape(separator)
          re_duplicate_separator        = /#{re_sep}{2,}/
          re_leading_trailing_separator = /^#{re_sep}|#{re_sep}$/i
        end
        # No more than one of the separator in a row.
        self.gsub!(re_duplicate_separator, separator)
        # Remove leading/trailing separator.
        self.gsub!(re_leading_trailing_separator, "")
      end

      self.downcase!
  end
end