This method can be used by developers wishing to debug the {APPROXIMATIONS} hashes, which are written in a hard-to-read format. @return Hash @example

 > ruby -rrubygems -rlib/friendly_id -e 'p FriendlyId::SlugString.dump_approximations'

{:common => {"À"=>"A", "Á"=>"A", "Â"=>"A", "Ã"=>"A", "Ä"=>"A", "Å"=>"A", "Æ"=>"AE", "Ç"=>"C", "È"=>"E", "É"=>"E", "Ê"=>"E", "Ë"=>"E", "Ì"=>"I", "Í"=>"I", "Î"=>"I", "Ï"=>"I", "Ð"=>"D", "Ñ"=>"N", "Ò"=>"O", "Ó"=>"O", "Ô"=>"O", "Õ"=>"O", "Ö"=>"O", "×"=>"x", "Ø"=>"O", "Ù"=>"U", "Ú"=>"U", "Û"=>"U", "Ü"=>"U", "Ý"=>"Y", "Þ"=>"Th", "ß"=>"ss", "à"=>"a", "á"=>"a", "â"=>"a", "ã"=>"a", "ä"=>"a", "å"=>"a", "æ"=>"ae", "ç"=>"c", "è"=>"e", "é"=>"e", "ê"=>"e", "ë"=>"e", "ì"=>"i", "í"=>"i", "î"=>"i", "ï"=>"i", "ð"=>"d", "ñ"=>"n", "ò"=>"o", "ó"=>"o", "ô"=>"o", "õ"=>"o", "ö"=>"o", "ø"=>"o", "ù"=>"u", "ú"=>"u", "û"=>"u", "ü"=>"u", "ý"=>"y", "þ"=>"th", "ÿ"=>"y", "Ā"=>"A", "ā"=>"a", "Ă"=>"A", "ă"=>"a", "Ą"=>"A", "ą"=>"a", "Ć"=>"C", "ć"=>"c", "Ĉ"=>"C", "ĉ"=>"c", "Ċ"=>"C", "ċ"=>"c", "Č"=>"C", "č"=>"c", "Ď"=>"D", "ď"=>"d", "Đ"=>"D", "đ"=>"d", "Ē"=>"E", "ē"=>"e", "Ĕ"=>"E", "ĕ"=>"e", "Ė"=>"E", "ė"=>"e", "Ę"=>"E", "ę"=>"e", "Ě"=>"E", "ě"=>"e", "Ĝ"=>"G", "ĝ"=>"g", "Ğ"=>"G", "ğ"=>"g", "Ġ"=>"G", "ġ"=>"g", "Ģ"=>"G", "ģ"=>"g", "Ĥ"=>"H", "ĥ"=>"h", "Ħ"=>"H", "ħ"=>"h", "Ĩ"=>"I", "ĩ"=>"i", "Ī"=>"I", "ī"=>"i", "Ĭ"=>"I", "ĭ"=>"i", "Į"=>"I", "į"=>"i", "İ"=>"I", "ı"=>"i", "IJ"=>"IJ", "ij"=>"ij", "Ĵ"=>"J", "ĵ"=>"j", "Ķ"=>"K", "ķ"=>"k", "ĸ"=>"k", "Ĺ"=>"L", "ĺ"=>"l", "Ļ"=>"L", "ļ"=>"l", "Ľ"=>"L", "ľ"=>"l", "Ŀ"=>"L", "ŀ"=>"l", "Ł"=>"L", "ł"=>"l", "Ń"=>"N", "ń"=>"n", "Ņ"=>"N", "ņ"=>"n", "Ň"=>"N", "ň"=>"n", "ʼn"=>"’n", "Ŋ"=>"NG", "ŋ"=>"ng", "Ō"=>"O", "ō"=>"o", "Ŏ"=>"O", "ŏ"=>"o", "Ő"=>"O", "ő"=>"o", "Œ"=>"OE", "œ"=>"oe", "Ŕ"=>"R", "ŕ"=>"r", "Ŗ"=>"R", "ŗ"=>"r", "Ř"=>"R", "ř"=>"r", "Ś"=>"S", "ś"=>"s", "Ŝ"=>"S", "ŝ"=>"s", "Ş"=>"S", "ş"=>"s", "Š"=>"S", "š"=>"s", "Ţ"=>"T", "ţ"=>"t", "Ť"=>"T", "ť"=>"t", "Ŧ"=>"T", "ŧ"=>"t", "Ũ"=>"U", "ũ"=>"u", "Ū"=>"U", "ū"=>"u", "Ŭ"=>"U", "ŭ"=>"u", "Ů"=>"U", "ů"=>"u", "Ű"=>"U", "ű"=>"u", "Ų"=>"U", "ų"=>"u", "Ŵ"=>"W", "ŵ"=>"w", "Ŷ"=>"Y", "ŷ"=>"y", "Ÿ"=>"Y", "Ź"=>"Z", "ź"=>"z", "Ż"=>"Z", "ż"=>"z", "Ž"=>"Z", "ž"=>"z"}, :german => {"ü"=>"ue", "ö"=>"oe", "ä"=>"ae"}, :spanish => {"Ñ"=>"Nn", "ñ"=>"nn"}}

@param string [String] The string to use as the basis of the SlugString.

Approximate an ASCII string. This works only for Western strings using characters that are Roman-alphabet characters + diacritics. Non-letter characters are left unmodified.

  string = SlugString.new "Łódź, Poland"
  string.approximate_ascii                 # => "Lodz, Poland"
  string = SlugString.new "日本"
  string.approximate_ascii                 # => "日本"

You can pass any key(s) from {APPROXIMATIONS} as arguments. This allows for contextual approximations. By default; +:spanish+ and +:german+ are provided:

  string = SlugString.new "Jürgen Müller"
  string.approximate_ascii                 # => "Jurgen Muller"
  string.approximate_ascii :german        # => "Juergen Mueller"
  string = SlugString.new "¡Feliz año!"
  string.approximate_ascii                 # => "¡Feliz ano!"
  string.approximate_ascii :spanish       # => "¡Feliz anno!"

You can modify the built-in approximations, or add your own:

  # Make Spanish use "nh" rather than "nn"
  FriendlyId::SlugString::APPROXIMATIONS[:spanish] = {
    # Ñ => "Nh"
    209 => [78, 104],
    # ñ => "nh"
    241 => [110, 104]
  }

It‘s also possible to use a custom approximation for all strings:

  FriendlyId::SlugString.approximations << :german

Notice that this method does not simply convert to ASCII; if you want to remove non-ASCII characters such as "¡" and "¿", use {to_ascii!}:

  string.approximate_ascii!(:spanish)       # => "¡Feliz anno!"
  string.to_ascii!                          # => "Feliz anno!"

@param *args <Symbol> @return String

Removes leading and trailing spaces or dashses, and replaces multiple whitespace characters with a single space. @return String

Lowercases the string. Note that this works for Unicode strings, though your milage may vary with Greek and Turkic strings. @return String

Normalize the string for use as a FriendlyId. Note that in this context, normalize means, strip, remove non-letters/numbers, downcasing and converting whitespace to dashes. ActiveSupport::Multibyte::Chars#normalize is aliased to +normalize_utf8+ in this subclass. @return String

Normalize the string for a given {FriendlyId::Configuration}. @param config [FriendlyId::Configuration] @return String

Delete any non-ascii characters. @return String

Truncate the string to max length. @return String

Upper-cases the string. Note that this works for Unicode strings, though your milage may vary with Greek and Turkic strings. @return String

Validate that the slug string is not blank or reserved, and truncate it to the max length if necessary. @param config [FriendlyId::Configuration] @return String @raise FriendlyId::BlankError @raise FriendlyId::ReservedError

Replaces whitespace with dashes ("-"). @return String

Remove any non-word characters. @return String