to_json

# File activesupport/lib/active_support/json/encoders/string.rb, line 25
  def to_json(options = nil) #:nodoc:
    json = '"' + gsub(ActiveSupport::JSON::Encoding.escape_regex) { |s|
      ActiveSupport::JSON::Encoding::ESCAPED_CHARS[s]
    }
    json.force_encoding('ascii-8bit') if respond_to?(:force_encoding)
    json.gsub(/([\xC0-\xDF][\x80-\xBF]|
             [\xE0-\xEF][\x80-\xBF]{2}|
             [\xF0-\xF7][\x80-\xBF]{3})+/nx) { |s|
      s.unpack("U*").pack("n*").unpack("H*")[0].gsub(/.{4}/, '\\\\u\&')
    } + '"'
  end