class String

def blank?
  # The regexp that matches blank strings is expensive. For the case of empty
  # strings we can speed up this method (~3.5x) with an empty? call. The
  # penalty for the rest of strings is marginal.
  empty? ||
    begin
      BLANK_RE.match?(self)
    rescue Encoding::CompatibilityError
      ENCODED_BLANKS[self.encoding].match?(self)
    end
end