meigyoku-thmn/iconv-lite

Convert character encodings in pure javascript.

iconv-lite: Pure JS character encoding conversion

• No need for native code compilation. Quick to install, 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, including Streaming support.
• In-browser usage via browserify or webpack (~180kb gzip compressed with Buffer shim included).
• Typescript type definition file included.
• React Native is supported (need to install stream module to enable Streaming API).
• License: MIT.

Usage

Basic API

var iconv = require("iconv-lite");

// Convert from an encoded buffer to a js string.
str = iconv.decode(Buffer.from([0x68, 0x65, 0x6c, 0x6c, 0x6f]), "win1251");

// Convert from a js string to an encoded buffer.
buf = iconv.encode("Sample input string", "win1251");

// Check if encoding is supported
iconv.encodingExists("us-ascii");

// Calculate the actual length in bytes.
len = iconv.byteLength("Hello, world! 😀", "utf16be");

// Get a decoder and decode two different buffers into a single string, the decoder keeps state between buffers
var utf8Decoder = iconv.getDecoder("utf8");
var bytes1 = Buffer.from([0x20, 0x23, 0xe2]); // space, # and part of ☣
var bytes2 = Buffer.from([0x98, 0xa3]); // the rest of ☣
var str = utf8Decoder.write(bytes1);
// You can check if the decoder has state currently
var hasState = utf8Decoder.hasState; // true;
str += utf8Decoder.write(bytes2);
var hasState = utf8Decoder.hasState; // false;

// The same for encoder, you rarely need to care about the encoder's state, except for some special encoders and surrogate pair
var utf8Encoder = iconv.getEncoder("utf8");
var bytes = utf8Encoder.write("Hi \uD83D");
var hasState = utf8Encoder.hasState; // true
bytes = bytes.concat([utf8Encoder.write("\uDE00")]);
hasState = utf8Encoder.hasState; // false

// Use the "end" method to get the remaining data in encoder/decoder's state and clear the state
var bytes = encoder.end();
var str = decoder.end();

Streaming API

// Decode stream (from binary data stream to js strings)
http.createServer(function (req, res) {
    var converterStream = iconv.decodeStream("win1251");
    req.pipe(converterStream);

    converterStream.on("data", function (str) {
        console.log(str); // Do something with decoded strings, chunk-by-chunk.
    });
});

// Convert encoding streaming example
fs.createReadStream("file-in-win1251.txt")
    .pipe(iconv.decodeStream("win1251"))
    .pipe(iconv.encodeStream("ucs2"))
    .pipe(fs.createWriteStream("file-in-ucs2.txt"));

// Sugar: all encode/decode streams have .collect(cb) method to accumulate data.
http.createServer(function (req, res) {
    req.pipe(iconv.decodeStream("win1251")).collect(function (err, body) {
        assert(typeof body == "string");
        console.log(body); // full request body string
    });
});

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, utf32, utf32-le, and utf32-be.
• 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.

operation             [email protected]   [email protected]
----------------------------------------------------------
encode('win1251')     ~96 Mb/s      ~320 Mb/s
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.

UTF-32 Encodings

This library supports UTF-32LE, UTF-32BE and UTF-32 encodings. Like the UTF-16 encoding above, UTF-32 defaults to UTF-32LE, but uses BOM and 'spaces heuristics' to determine input endianness.

• The default of UTF-32LE can be overridden with the defaultEncoding: 'utf-32be' option. Strips BOM unless stripBOM: false.
• Encoding: uses UTF-32LE and writes BOM by default. Use addBOM: false to override. (defaultEncoding: 'utf-32be' can also be used here to change encoding.)

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

$ git clone [email protected]:ashtuchkin/iconv-lite.git
$ cd iconv-lite
$ npm install
$ npm test

$ # To view performance:
$ node test/performance.js

$ # To view test coverage:
$ npm run coverage
$ open coverage/lcov-report/index.html