README.md

## Pure JS character encoding conversion [![Build Status](https://travis-ci.org/ashtuchkin/iconv-lite.svg?branch=master)](https://travis-ci.org/ashtuchkin/iconv-lite)

 * Doesn't need native code compilation. Works on Windows and in sandboxed environments like [Cloud9](http://c9.io).
 * Used in popular projects like [Express.js (body_parser)](https://github.com/expressjs/body-parser), 
   [Grunt](http://gruntjs.com/), [Nodemailer](http://www.nodemailer.com/), [Yeoman](http://yeoman.io/) and others.
 * Faster than [node-iconv](https://github.com/bnoordhuis/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](https://github.com/substack/node-browserify) (~180k gzip compressed with Buffer shim included).
 * Typescript [type definition file](https://github.com/ashtuchkin/iconv-lite/blob/master/lib/index.d.ts) included.
 * React Native is supported (need to explicitly `npm install` two more modules: `buffer` and `stream`).
 * License: MIT.

[![NPM Stats](https://nodei.co/npm/iconv-lite.png?downloads=true&downloadRank=true)](https://npmjs.org/packages/iconv-lite/)

## Usage
### Basic API
```javascript
var iconv = require('iconv-lite');

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

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

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

### Streaming API (Node v0.10+)
```javascript

// Decode stream (from binary 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
    });
});
```

### [Deprecated] Extend Node.js own encodings
> NOTE: This doesn't work on latest Node versions. See [details](https://github.com/ashtuchkin/iconv-lite/wiki/Node-v4-compatibility).

```javascript
// After this call all Node basic primitives will understand iconv-lite encodings.
iconv.extendNodeEncodings();

// Examples:
buf = new Buffer(str, 'win1251');
buf.write(str, 'gbk');
str = buf.toString('latin1');
assert(Buffer.isEncoding('iso-8859-15'));
Buffer.byteLength(str, 'us-ascii');

http.createServer(function(req, res) {
    req.setEncoding('big5');
    req.collect(function(err, body) {
        console.log(body);
    });
});

fs.createReadStream("file.txt", "shift_jis");

// External modules are also supported (if they use Node primitives, which they probably do).
request = require('request');
request({
    url: "http://github.com/", 
    encoding: "cp932"
});

// To remove extensions
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](https://github.com/ashtuchkin/iconv-lite/wiki/Supported-Encodings).

Most singlebyte encodings are generated automatically from [node-iconv](https://github.com/bnoordhuis/node-iconv). Thank you Ben Noordhuis and libiconv authors!

Multibyte encodings are generated from [Unicode.org mappings](http://www.unicode.org/Public/MAPPINGS/) and [WHATWG Encoding Standard mappings](http://encoding.spec.whatwg.org/). 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             iconv@2.1.4   iconv-lite@0.4.7
    ----------------------------------------------------------
    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](https://github.com/danielgindi/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](https://github.com/ashtuchkin/iconv-lite/wiki/Use-Buffers-when-decoding).  
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

```bash
$ git clone git@github.com: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
```