The Punycode Module in Node.js

1. Introduction

Punycode is a character encoding scheme that converts Unicode strings into ASCII-only strings. It is primarily used for domain names containing non-ASCII characters, ensuring compatibility with DNS and URL systems.

const punycode = require('node:punycode');

2. Core Methods

• punycode.encode(string): Converts Unicode strings to Punycode.
• punycode.decode(string): Converts Punycode strings back to Unicode.

punycode.encode('mañana'); // 'maana-pta'
punycode.decode('maana-pta'); // 'mañana'

3. Domain Conversion

• punycode.toASCII(domain): Converts Unicode domain names to Punycode.
• punycode.toUnicode(domain): Converts Punycode domain names back to Unicode.

punycode.toASCII('mañana.com');  // 'xn--maana-pta.com'
punycode.toUnicode('xn--maana-pta.com'); // 'mañana.com'

4. UCS2 Utilities

• punycode.ucs2.decode(string): Returns an array of Unicode code points.
• punycode.ucs2.encode(codePoints): Builds a string from an array of code points.

punycode.ucs2.decode('abc'); // [0x61, 0x62, 0x63]
punycode.ucs2.encode([0x61, 0x62, 0x63]); // 'abc'

5. Version

• punycode.version: Returns the current Punycode.js version string.

6. Deprecation and Alternatives

The punycode module is deprecated and will be removed in future Node.js releases. Recommended alternatives include:

• The standalone Punycode.js library.
• url.domainToASCII or the WHATWG URL API for domain encoding.

Conclusion

The punycode module provided a convenient way to handle internationalized domain names in Node.js. However, with its deprecation, developers should adopt modern APIs or external libraries to ensure compatibility and future-proof applications.