mirror of
https://github.com/titanscouting/tra-analysis.git
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157 lines
6.4 KiB
Markdown
157 lines
6.4 KiB
Markdown
## Pure JS character encoding conversion [](https://travis-ci.org/ashtuchkin/iconv-lite)
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* Doesn't need native code compilation. Works on Windows and in sandboxed environments like [Cloud9](http://c9.io).
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* Used in popular projects like [Express.js (body_parser)](https://github.com/expressjs/body-parser),
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[Grunt](http://gruntjs.com/), [Nodemailer](http://www.nodemailer.com/), [Yeoman](http://yeoman.io/) and others.
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* Faster than [node-iconv](https://github.com/bnoordhuis/node-iconv) (see below for performance comparison).
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* Intuitive encode/decode API
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* Streaming support for Node v0.10+
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* [Deprecated] Can extend Node.js primitives (buffers, streams) to support all iconv-lite encodings.
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* In-browser usage via [Browserify](https://github.com/substack/node-browserify) (~180k gzip compressed with Buffer shim included).
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* Typescript [type definition file](https://github.com/ashtuchkin/iconv-lite/blob/master/lib/index.d.ts) included.
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* React Native is supported (need to explicitly `npm install` two more modules: `buffer` and `stream`).
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* License: MIT.
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[](https://npmjs.org/packages/iconv-lite/)
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## Usage
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### Basic API
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```javascript
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var iconv = require('iconv-lite');
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// Convert from an encoded buffer to js string.
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str = iconv.decode(Buffer.from([0x68, 0x65, 0x6c, 0x6c, 0x6f]), 'win1251');
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// Convert from js string to an encoded buffer.
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buf = iconv.encode("Sample input string", 'win1251');
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// Check if encoding is supported
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iconv.encodingExists("us-ascii")
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```
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### Streaming API (Node v0.10+)
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```javascript
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// Decode stream (from binary stream to js strings)
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http.createServer(function(req, res) {
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var converterStream = iconv.decodeStream('win1251');
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req.pipe(converterStream);
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converterStream.on('data', function(str) {
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console.log(str); // Do something with decoded strings, chunk-by-chunk.
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});
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});
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// Convert encoding streaming example
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fs.createReadStream('file-in-win1251.txt')
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.pipe(iconv.decodeStream('win1251'))
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.pipe(iconv.encodeStream('ucs2'))
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.pipe(fs.createWriteStream('file-in-ucs2.txt'));
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// Sugar: all encode/decode streams have .collect(cb) method to accumulate data.
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http.createServer(function(req, res) {
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req.pipe(iconv.decodeStream('win1251')).collect(function(err, body) {
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assert(typeof body == 'string');
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console.log(body); // full request body string
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});
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});
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```
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### [Deprecated] Extend Node.js own encodings
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> NOTE: This doesn't work on latest Node versions. See [details](https://github.com/ashtuchkin/iconv-lite/wiki/Node-v4-compatibility).
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```javascript
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// After this call all Node basic primitives will understand iconv-lite encodings.
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iconv.extendNodeEncodings();
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// Examples:
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buf = new Buffer(str, 'win1251');
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buf.write(str, 'gbk');
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str = buf.toString('latin1');
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assert(Buffer.isEncoding('iso-8859-15'));
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Buffer.byteLength(str, 'us-ascii');
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http.createServer(function(req, res) {
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req.setEncoding('big5');
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req.collect(function(err, body) {
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console.log(body);
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});
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});
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fs.createReadStream("file.txt", "shift_jis");
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// External modules are also supported (if they use Node primitives, which they probably do).
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request = require('request');
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request({
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url: "http://github.com/",
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encoding: "cp932"
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});
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// To remove extensions
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iconv.undoExtendNodeEncodings();
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```
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## Supported encodings
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* All node.js native encodings: utf8, ucs2 / utf16-le, ascii, binary, base64, hex.
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* Additional unicode encodings: utf16, utf16-be, utf-7, utf-7-imap.
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* All widespread singlebyte encodings: Windows 125x family, ISO-8859 family,
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IBM/DOS codepages, Macintosh family, KOI8 family, all others supported by iconv library.
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Aliases like 'latin1', 'us-ascii' also supported.
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* All widespread multibyte encodings: CP932, CP936, CP949, CP950, GB2312, GBK, GB18030, Big5, Shift_JIS, EUC-JP.
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See [all supported encodings on wiki](https://github.com/ashtuchkin/iconv-lite/wiki/Supported-Encodings).
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Most singlebyte encodings are generated automatically from [node-iconv](https://github.com/bnoordhuis/node-iconv). Thank you Ben Noordhuis and libiconv authors!
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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!
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## Encoding/decoding speed
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Comparison with node-iconv module (1000x256kb, on MacBook Pro, Core i5/2.6 GHz, Node v0.12.0).
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Note: your results may vary, so please always check on your hardware.
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operation iconv@2.1.4 iconv-lite@0.4.7
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----------------------------------------------------------
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encode('win1251') ~96 Mb/s ~320 Mb/s
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decode('win1251') ~95 Mb/s ~246 Mb/s
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## BOM handling
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* Decoding: BOM is stripped by default, unless overridden by passing `stripBOM: false` in options
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(f.ex. `iconv.decode(buf, enc, {stripBOM: false})`).
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A callback might also be given as a `stripBOM` parameter - it'll be called if BOM character was actually found.
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* 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.
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* Encoding: No BOM added, unless overridden by `addBOM: true` option.
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## UTF-16 Encodings
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This library supports UTF-16LE, UTF-16BE and UTF-16 encodings. First two are straightforward, but UTF-16 is trying to be
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smart about endianness in the following ways:
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* Decoding: uses BOM and 'spaces heuristic' to determine input endianness. Default is UTF-16LE, but can be
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overridden with `defaultEncoding: 'utf-16be'` option. Strips BOM unless `stripBOM: false`.
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* Encoding: uses UTF-16LE and writes BOM by default. Use `addBOM: false` to override.
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## Other notes
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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).
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Untranslatable characters are set to <20> or ?. No transliteration is currently supported.
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Node versions 0.10.31 and 0.11.13 are buggy, don't use them (see #65, #77).
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## Testing
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```bash
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$ git clone git@github.com:ashtuchkin/iconv-lite.git
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$ cd iconv-lite
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$ npm install
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$ npm test
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$ # To view performance:
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$ node test/performance.js
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$ # To view test coverage:
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$ npm run coverage
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$ open coverage/lcov-report/index.html
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```
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