# Punycode.js [](https://travis-ci.org/bestiejs/punycode.js) [](https://coveralls.io/r/bestiejs/punycode.js) [](https://gemnasium.com/bestiejs/punycode.js) A robust Punycode converter that fully complies to [RFC 3492](https://tools.ietf.org/html/rfc3492) and [RFC 5891](https://tools.ietf.org/html/rfc5891), and works on nearly all JavaScript platforms. This JavaScript library is the result of comparing, optimizing and documenting different open-source implementations of the Punycode algorithm: * [The C example code from RFC 3492](https://tools.ietf.org/html/rfc3492#appendix-C) * [`punycode.c` by _Markus W. Scherer_ (IBM)](http://opensource.apple.com/source/ICU/ICU-400.42/icuSources/common/punycode.c) * [`punycode.c` by _Ben Noordhuis_](https://github.com/bnoordhuis/punycode/blob/master/punycode.c) * [JavaScript implementation by _some_](http://stackoverflow.com/questions/183485/can-anyone-recommend-a-good-free-javascript-for-punycode-to-unicode-conversion/301287#301287) * [`punycode.js` by _Ben Noordhuis_](https://github.com/joyent/node/blob/426298c8c1c0d5b5224ac3658c41e7c2a3fe9377/lib/punycode.js) (note: [not fully compliant](https://github.com/joyent/node/issues/2072)) This project is [bundled](https://github.com/joyent/node/blob/master/lib/punycode.js) with [Node.js v0.6.2+](https://github.com/joyent/node/compare/975f1930b1...61e796decc) and [io.js v1.0.0+](https://github.com/iojs/io.js/blob/v1.x/lib/punycode.js). ## Installation Via [npm](https://www.npmjs.com/) (only required for Node.js releases older than v0.6.2): ```bash npm install punycode ``` Via [Bower](http://bower.io/): ```bash bower install punycode ``` Via [Component](https://github.com/component/component): ```bash component install bestiejs/punycode.js ``` In a browser: ```html <script src="punycode.js"></script> ``` In [Node.js](https://nodejs.org/), [io.js](https://iojs.org/), [Narwhal](http://narwhaljs.org/), and [RingoJS](http://ringojs.org/): ```js var punycode = require('punycode'); ``` In [Rhino](http://www.mozilla.org/rhino/): ```js load('punycode.js'); ``` Using an AMD loader like [RequireJS](http://requirejs.org/): ```js require( { 'paths': { 'punycode': 'path/to/punycode' } }, ['punycode'], function(punycode) { console.log(punycode); } ); ``` ## API ### `punycode.decode(string)` Converts a Punycode string of ASCII symbols to a string of Unicode symbols. ```js // decode domain name parts punycode.decode('maana-pta'); // 'mañana' punycode.decode('--dqo34k'); // '☃-⌘' ``` ### `punycode.encode(string)` Converts a string of Unicode symbols to a Punycode string of ASCII symbols. ```js // encode domain name parts punycode.encode('mañana'); // 'maana-pta' punycode.encode('☃-⌘'); // '--dqo34k' ``` ### `punycode.toUnicode(input)` 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. ```js // 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' ``` ### `punycode.toASCII(input)` 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. ```js // 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' ``` ### `punycode.ucs2` #### `punycode.ucs2.decode(string)` Creates an array containing the numeric code point values of each Unicode symbol in the string. While [JavaScript uses UCS-2 internally](https://mathiasbynens.be/notes/javascript-encoding), 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. ```js punycode.ucs2.decode('abc'); // → [0x61, 0x62, 0x63] // surrogate pair for U+1D306 TETRAGRAM FOR CENTRE: punycode.ucs2.decode('\uD834\uDF06'); // → [0x1D306] ``` #### `punycode.ucs2.encode(codePoints)` Creates a string based on an array of numeric code point values. ```js punycode.ucs2.encode([0x61, 0x62, 0x63]); // → 'abc' punycode.ucs2.encode([0x1D306]); // → '\uD834\uDF06' ``` ### `punycode.version` A string representing the current Punycode.js version number. ## Unit tests & code coverage After cloning this repository, run `npm install --dev` to install the dependencies needed for Punycode.js development and testing. You may want to install Istanbul _globally_ using `npm install istanbul -g`. Once that’s done, you can run the unit tests in Node using `npm test` or `node tests/tests.js`. To run the tests in Rhino, Ringo, Narwhal, PhantomJS, and web browsers as well, use `grunt test`. To generate the code coverage report, use `grunt cover`. Feel free to fork if you see possible improvements! ## Author | [](https://twitter.com/mathias "Follow @mathias on Twitter") | |---| | [Mathias Bynens](https://mathiasbynens.be/) | ## Contributors | [](https://twitter.com/jdalton "Follow @jdalton on Twitter") | |---| | [John-David Dalton](http://allyoucanleet.com/) | ## License Punycode.js is available under the [MIT](https://mths.be/mit) license.