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punycode

A robust Punycode converter that fully complies to RFC 3492 and RFC 5891, and works on nearly all JavaScript platforms.

Punycode.js

Punycode.js is a robust Punycode converter that fully complies to RFC 3492 and RFC 5891.

This JavaScript library is the result of comparing, optimizing and documenting different open-source implementations of the Punycode algorithm:

This project is bundled with Node.js v0.6.2+ and io.js v1.0.0+.

The current version supports recent versions of Node.js only. For the old version that offers the same functionality with broader support, including Rhino, Ringo, Narwhal, and web browsers, see v1.4.1.

Via npm (only required for Node.js releases older than v0.6.2):

npm install punycode

In Node.js:

const punycode = require('punycode');

Converts a Punycode string of ASCII symbols to a string of Unicode symbols.

// decode domain name parts 
punycode.decode('maana-pta'); // 'mañana' 
punycode.decode('--dqo34k'); // '☃-⌘' 

Converts a string of Unicode symbols to a Punycode string of ASCII symbols.

// encode domain name parts 
punycode.encode('mañana'); // 'maana-pta' 
punycode.encode('☃-⌘'); // '--dqo34k' 

Converts a Punycode string representing a domain name or an email address to Unicode. Only the Punycoded parts of the input will be converted, i.e. it doesn’t matter if you call it on a string that has already been converted to Unicode.

// decode domain names 
punycode.toUnicode('xn--maana-pta.com');
// → 'mañana.com' 
punycode.toUnicode('xn----dqo34k.com');
// → '☃-⌘.com' 
 
// decode email addresses 
punycode.toUnicode('джумла@xn--p-8sbkgc5ag7bhce.xn--ba-lmcq');
// → 'джумла@джpумлатест.bрфa' 

Converts a lowercased Unicode string representing a domain name or an email address to Punycode. Only the non-ASCII parts of the input will be converted, i.e. it doesn’t matter if you call it with a domain that’s already in ASCII.

// encode domain names 
punycode.toASCII('mañana.com');
// → 'xn--maana-pta.com' 
punycode.toASCII('☃-⌘.com');
// → 'xn----dqo34k.com' 
 
// encode email addresses 
punycode.toASCII('джумла@джpумлатест.bрфa');
// → 'джумла@xn--p-8sbkgc5ag7bhce.xn--ba-lmcq' 

Creates an array containing the numeric code point values of each Unicode symbol in the string. While JavaScript uses UCS-2 internally, this function will convert a pair of surrogate halves (each of which UCS-2 exposes as separate characters) into a single code point, matching UTF-16.

punycode.ucs2.decode('abc');
// → [0x61, 0x62, 0x63] 
// surrogate pair for U+1D306 TETRAGRAM FOR CENTRE: 
punycode.ucs2.decode('\uD834\uDF06');
// → [0x1D306] 

Creates a string based on an array of numeric code point values.

punycode.ucs2.encode([0x61, 0x62, 0x63]);
// → 'abc' 
punycode.ucs2.encode([0x1D306]);
// → '\uD834\uDF06' 

A string representing the current Punycode.js version number.

Mathias Bynens

Punycode.js is available under the MIT license.