nodejs/doc/api/punycode.markdown

# punycode

    Stability: 2 - Unstable

[Punycode.js](http://mths.be/punycode) is bundled with Node.js v0.6.2+. Use
`require('punycode')` to access it. (To use it with other Node.js versions,
use npm to install the `punycode` module first.)

## punycode.decode(string)

Converts a Punycode string of ASCII code points to a string of Unicode code
points.

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

## punycode.encode(string)

Converts a string of Unicode code points to a Punycode string of ASCII code
points.

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

## punycode.toUnicode(domain)

Converts a Punycode string representing a domain name to Unicode. Only the
Punycoded parts of the domain name 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'

## punycode.toASCII(domain)

Converts a Unicode string representing a domain name to Punycode. Only the
non-ASCII parts of the domain name 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'

## punycode.ucs2

### punycode.ucs2.decode(string)

Creates an array containing the decimal code points of each Unicode character
in the string. While [JavaScript uses UCS-2
internally](http://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.

    punycode.ucs2.decode('abc'); // [97, 98, 99]
    // 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 decimal code points.

    punycode.ucs2.encode([97, 98, 99]); // 'abc'
    punycode.ucs2.encode([0x1D306]); // '\uD834\uDF06'

## punycode.version

A string representing the current Punycode.js version number.