Pure JS character encoding conversion Build Status

  • Doesn’t need native code compilation. Works on Windows and in sandboxed environments like Cloud9.
  • Used in popular projects like Express.js (body_parser), Grunt, Nodemailer, Yeoman and others.
  • Faster than node-iconv (see below for performance comparison).
  • Intuitive encode/decode API
  • Streaming support for Node v0.10+
  • [Deprecated] Can extend Node.js primitives (buffers, streams) to support all iconv-lite encodings.
  • In-browser usage via Browserify (~180k gzip compressed with Buffer shim included).
  • Typescript type definition file included.
  • React Native is supported (need to explicitly npm install two more modules: buffer and stream).
  • License: MIT.

NPM Stats

Usage

Basic API

  1. var iconv = require('iconv-lite');
  3. // Convert from an encoded buffer to js string.
  4. str = iconv.decode(Buffer.from([0x68, 0x65, 0x6c, 0x6c, 0x6f]), 'win1251');
  6. // Convert from js string to an encoded buffer.
  7. buf = iconv.encode("Sample input string", 'win1251');
  9. // Check if encoding is supported
  10. iconv.encodingExists("us-ascii")

Streaming API (Node v0.10+)

  2. // Decode stream (from binary stream to js strings)
  3. http.createServer(function(req, res) {
  4.     var converterStream = iconv.decodeStream('win1251');
  5.     req.pipe(converterStream);
  7.     converterStream.on('data', function(str) {
  8.         console.log(str); // Do something with decoded strings, chunk-by-chunk.
  9.     });
  10. });
  12. // Convert encoding streaming example
  13. fs.createReadStream('file-in-win1251.txt')
  14.     .pipe(iconv.decodeStream('win1251'))
  15.     .pipe(iconv.encodeStream('ucs2'))
  16.     .pipe(fs.createWriteStream('file-in-ucs2.txt'));
  18. // Sugar: all encode/decode streams have .collect(cb) method to accumulate data.
  19. http.createServer(function(req, res) {
  20.     req.pipe(iconv.decodeStream('win1251')).collect(function(err, body) {
  21.         assert(typeof body == 'string');
  22.         console.log(body); // full request body string
  23.     });
  24. });

[Deprecated] Extend Node.js own encodings

NOTE: This doesn’t work on latest Node versions. See details.

  1. // After this call all Node basic primitives will understand iconv-lite encodings.
  2. iconv.extendNodeEncodings();
  4. // Examples:
  5. buf = new Buffer(str, 'win1251');
  6. buf.write(str, 'gbk');
  7. str = buf.toString('latin1');
  8. assert(Buffer.isEncoding('iso-8859-15'));
  9. Buffer.byteLength(str, 'us-ascii');
  11. http.createServer(function(req, res) {
  12.     req.setEncoding('big5');
  13.     req.collect(function(err, body) {
  14.         console.log(body);
  15.     });
  16. });
  18. fs.createReadStream("file.txt", "shift_jis");
  20. // External modules are also supported (if they use Node primitives, which they probably do).
  21. request = require('request');
  22. request({
  23.     url: "http://github.com/", 
  24.     encoding: "cp932"
  25. });
  27. // To remove extensions
  28. iconv.undoExtendNodeEncodings();

Supported encodings

  • All node.js native encodings: utf8, ucs2 / utf16-le, ascii, binary, base64, hex.
  • Additional unicode encodings: utf16, utf16-be, utf-7, utf-7-imap.
  • All widespread singlebyte encodings: Windows 125x family, ISO-8859 family, IBM/DOS codepages, Macintosh family, KOI8 family, all others supported by iconv library. Aliases like ‘latin1’, ‘us-ascii’ also supported.
  • All widespread multibyte encodings: CP932, CP936, CP949, CP950, GB2312, GBK, GB18030, Big5, Shift_JIS, EUC-JP.

See all supported encodings on wiki.

Most singlebyte encodings are generated automatically from node-iconv. Thank you Ben Noordhuis and libiconv authors!

Multibyte encodings are generated from Unicode.org mappings and WHATWG Encoding Standard mappings. Thank you, respective authors!

Encoding/decoding speed

Comparison with node-iconv module (1000x256kb, on MacBook Pro, Core i5/2.6 GHz, Node v0.12.0). Note: your results may vary, so please always check on your hardware.

  1. operation             iconv@2.1.4   iconv-lite@0.4.7
  2. ----------------------------------------------------------
  3. encode('win1251')     ~96 Mb/s      ~320 Mb/s
  4. decode('win1251')     ~95 Mb/s      ~246 Mb/s

BOM handling

  • Decoding: BOM is stripped by default, unless overridden by passing stripBOM: false in options (f.ex. iconv.decode(buf, enc, {stripBOM: false})). A callback might also be given as a stripBOM parameter - it’ll be called if BOM character was actually found.
  • If you want to detect UTF-8 BOM when decoding other encodings, use node-autodetect-decoder-stream module.
  • Encoding: No BOM added, unless overridden by addBOM: true option.

UTF-16 Encodings

This library supports UTF-16LE, UTF-16BE and UTF-16 encodings. First two are straightforward, but UTF-16 is trying to be smart about endianness in the following ways:

  • Decoding: uses BOM and ‘spaces heuristic’ to determine input endianness. Default is UTF-16LE, but can be overridden with defaultEncoding: 'utf-16be' option. Strips BOM unless stripBOM: false.
  • Encoding: uses UTF-16LE and writes BOM by default. Use addBOM: false to override.

Other notes

When decoding, be sure to supply a Buffer to decode() method, otherwise bad things usually happen.
Untranslatable characters are set to � or ?. No transliteration is currently supported.
Node versions 0.10.31 and 0.11.13 are buggy, don’t use them (see #65, #77).

Testing

  1. $ git clone git@github.com:ashtuchkin/iconv-lite.git
  2. $ cd iconv-lite
  3. $ npm install
  4. $ npm test
  6. $ # To view performance:
  7. $ node test/performance.js
  9. $ # To view test coverage:
  10. $ npm run coverage
  11. $ open coverage/lcov-report/index.html