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:
- The C example code from RFC 3492
punycode.cby Markus W. Scherer (IBM)punycode.cby Ben Noordhuis- JavaScript implementation by some
punycode.jsby Ben Noordhuis (note: not fully compliant)
This project was bundled with Node.js from v0.6.2+ until v7 (soft-deprecated).
The current version supports recent versions of Node.js only. It provides a CommonJS module and an ES6 module. For the old version that offers the same functionality with broader support, including Rhino, Ringo, Narwhal, and web browsers, see v1.4.1.
Installation
Via npm:
npm install punycode --save
In Node.js:
const punycode = require('punycode');
API
punycode.decode(string)
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'); // '☃-⌘'
punycode.encode(string)
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'
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.
// 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.
// 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, 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]
punycode.ucs2.encode(codePoints)
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'
punycode.version
A string representing the current Punycode.js version number.
Author, 
, ---, Mathias Bynens, ## License
Punycode.js is available under the MIT license.