Node.js Punycode

Punycode is a standard for encoding and decoding internationalized domain names (IDN). It is used to convert Unicode characters into ASCII-compatible characters that can be used in a DNS name.

Node.js provides a built-in module for Punycode encoding and decoding, which can be used for handling IDNs in your JavaScript code.

Installation

Punycode is included in the Node.js core, so there is no need to install it separately.

Encoding

To encode a Unicode string to its Punycode equivalent, use the punycode.encode() method:

const punycode = require('punycode');

const unicodeString = '你好';
const punycodeString = punycode.encode(unicodeString);

console.log(punycodeString); // 'www.xn--6qqa88b'

Here, we convert the Unicode string "你好" to its Punycode equivalent "www.xn--6qqa88b".

Decoding

To decode a Punycode string to its Unicode equivalent, use the punycode.decode() method:

const punycode = require('punycode');

const punycodeString = 'www.xn--6qqa88b';
const unicodeString = punycode.decode(punycodeString);

console.log(unicodeString); // '你好'

Here, we convert the Punycode string "www.xn--6qqa88b" to its Unicode equivalent "你好".

Encoding and Decoding URLs

Sometimes, you may need to encode or decode a URL that contains Punycode-encoded characters. Node.js provides the punycode.toASCII() and punycode.toUnicode() methods for this purpose.

Here's an example of how to encode a URL that contains Punycode-encoded characters:

const punycode = require('punycode');

const url = 'https://www.xn--6qqa88b.com';
const encodedUrl = punycode.toASCII(url);

console.log(encodedUrl); // 'https://www.xn--6qqa88b.com'

And here's an example of how to decode a URL that contains Punycode-encoded characters:

const punycode = require('punycode');

const encodedUrl = 'https://www.xn--6qqa88b.com';
const decodedUrl = punycode.toUnicode(encodedUrl);

console.log(decodedUrl); // 'https://www.你好.com'

Note that if the input string already contains Unicode characters, these methods will leave them unchanged.

Conclusion

In this tutorial, we've learned how to use the Punycode module in Node.js to encode and decode IDNs. This can be very helpful when working with internationalization in your JavaScript code.