@meigyokuthmn/iconv-lite
v0.7.0-pre
Published
Convert character encodings in pure javascript.
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105
Readme
Warning: This package is a fork from an old version of iconv-lite and is supposed to be used internally by CSBinary only, it's not supposed to be used publicly. Please navigate to https://www.npmjs.com/package/iconv-lite to use the lastest version of iconv-lite.
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 astripBOM
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 unlessstripBOM: 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 unlessstripBOM: 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