node-iconv

Text recoding in JavaScript for fun and profit!

Supported encodings

European languages
    ASCII, ISO-8859-{1,2,3,4,5,7,9,10,13,14,15,16},
    KOI8-R, KOI8-U, KOI8-RU,
    CP{437,737,775,850,852,853,855,857,858,860,861,863,865,866,869}
    CP{1125,1250,1251,1252,1253,1254,1257}
    Mac{Roman,CentralEurope,Iceland,Croatian,Romania},
    Mac{Cyrillic,Ukraine,Greek,Turkish},
    Macintosh
Semitic languages
    ISO-8859-{6,8}, CP{1255,1256}, CP862, CP864, Mac{Hebrew,Arabic}
Japanese
    EUC-JP, SHIFT_JIS, CP932, ISO-2022-JP, ISO-2022-JP-2, ISO-2022-JP-1
    EUC-JISX0213, Shift_JISX0213, ISO-2022-JP-3
Chinese
    EUC-CN, HZ, GBK, CP936, GB18030, EUC-TW, BIG5, CP950, BIG5-HKSCS,
    BIG5-HKSCS:2004, BIG5-HKSCS:2001, BIG5-HKSCS:1999, ISO-2022-CN,
    ISO-2022-CN-EXT, BIG5-2003 (experimental)
Korean
    EUC-KR, CP949, ISO-2022-KR, JOHAB
Turkmen
    TDS565
Armenian
    ARMSCII-8
Georgian
    Georgian-Academy, Georgian-PS
Tajik
    KOI8-T
Kazakh
    PT154, RK1048
Thai
    ISO-8859-11, TIS-620, CP874, MacThai
Laotian
    MuleLao-1, CP1133
Vietnamese
    VISCII, TCVN, CP1258
Platform specifics
    HP-ROMAN8, NEXTSTEP, ATARIST, RISCOS-LATIN1
Full Unicode
    UTF-8
    UCS-2, UCS-2BE, UCS-2LE
    UCS-4, UCS-4BE, UCS-4LE
    UTF-16, UTF-16BE, UTF-16LE
    UTF-32, UTF-32BE, UTF-32LE
    UTF-7
    C99, JAVA
Full Unicode, in terms of `uint16_t` or `uint32_t`
    (with machine dependent endianness and alignment)
    UCS-2-INTERNAL, UCS-4-INTERNAL
Locale dependent, in terms of `char` or `wchar_t`
    (with machine dependent endianness and alignment, and with OS and
    locale dependent semantics)
    char, wchar_t
    The empty encoding name "" is equivalent to "char": it denotes the
    locale dependent character encoding.

If you don't need the full gamut of encodings, consider using iconv-lite. It supports most common encodings and doesn't require a compiler to install.

Installing with npm

$ npm install iconv

Note that you do not need to have a copy of libiconv installed to use this module.

Compiling from source

$ git clone git://github.com/bnoordhuis/node-iconv.git
$ cd node-iconv
$ npm install

If you have a specific node.js source checkout that you want to build against, replace the last command with:

$ npm install --nodedir=/path/to/node

Usage

Encode from one character encoding to another:

// convert from UTF-8 to ISO-8859-1
var Buffer = require('buffer').Buffer;
var Iconv  = require('iconv').Iconv;
var assert = require('assert');

var iconv = new Iconv('UTF-8', 'ISO-8859-1');
var buffer = iconv.convert('Hello, world!');
var buffer2 = iconv.convert(new Buffer('Hello, world!'));
assert.equals(buffer.inspect(), buffer2.inspect());
// do something useful with the buffers

A simple ISO-8859-1 to UTF-8 conversion TCP service:

var net = require('net');
var Iconv = require('iconv').Iconv;
var server = net.createServer(function(conn) {
  var iconv = new Iconv('latin1', 'utf-8');
  conn.pipe(iconv).pipe(conn);
});
server.listen(8000);
console.log('Listening on tcp://0.0.0.0:8000/');

Look at test/test-basic.js and test/test-stream.js for more examples and node-iconv's behaviour under error conditions.

Notes

Things to keep in mind when you work with node-iconv.

Chunked data

Say you are reading data in chunks from a HTTP stream. The logical input is a single document (the full POST request data) but the physical input will be spread over several buffers (the request chunks).

You must accumulate the small buffers into a single large buffer before performing the conversion. If you don't, you will get unexpected results with multi-byte and stateful character sets like UTF-8 and ISO-2022-JP.

The above only applies when you are calling Iconv#convert() yourself. If you use the streaming interface, node-iconv takes care of stitching partial character sequences together again.

Dealing with untranslatable characters

Characters are not always translatable to another encoding. The UTF-8 string "ça va が", for example, cannot be represented in plain 7-bits ASCII without some loss of fidelity.

By default, node-iconv throws EILSEQ when untranslatabe characters are encountered but this can be customized. Quoting the iconv_open(3) man page:

//TRANSLIT
When  the  string  "//TRANSLIT"  is appended to tocode, transliteration is
activated. This means that when a character cannot be represented in the
target character set, it can be approximated through one or several
similarly looking characters.

//IGNORE
When the string "//IGNORE" is appended to tocode, characters that cannot be
represented in the target character set will be silently discarded.

Example usage:

var iconv = new Iconv('UTF-8', 'ASCII');
iconv.convert('ça va'); // throws EILSEQ

var iconv = new Iconv('UTF-8', 'ASCII//IGNORE');
iconv.convert('ça va'); // returns "a va"

var iconv = new Iconv('UTF-8', 'ASCII//TRANSLIT');
iconv.convert('ça va'); // "ca va"

var iconv = new Iconv('UTF-8', 'ASCII//TRANSLIT//IGNORE');
iconv.convert('ça va が'); // "ca va "

EINVAL

EINVAL is raised when the input ends in a partial character sequence. This is a feature, not a bug.