86 lines
3.6 KiB
Markdown
86 lines
3.6 KiB
Markdown
# utf8.js [](https://travis-ci.org/mathiasbynens/utf8.js) [](https://coveralls.io/r/mathiasbynens/utf8.js) [](https://gemnasium.com/mathiasbynens/utf8.js)
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_utf8.js_ is a well-tested UTF-8 encoder/decoder written in JavaScript. Unlike many other JavaScript solutions, it is designed to be a _proper_ UTF-8 encoder/decoder: it can encode/decode any scalar Unicode code point values, as per [the Encoding Standard](https://encoding.spec.whatwg.org/#utf-8). [Here’s an online demo.](https://mothereff.in/utf-8)
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Feel free to fork if you see possible improvements!
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## Installation
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Via [npm](https://www.npmjs.com/):
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```bash
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npm install utf8
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```
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In a browser:
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```html
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<script src="utf8.js"></script>
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```
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In [Node.js](https://nodejs.org/):
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```js
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const utf8 = require('utf8');
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```
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## API
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### `utf8.encode(string)`
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Encodes any given JavaScript string (`string`) as UTF-8, and returns the UTF-8-encoded version of the string. It throws an error if the input string contains a non-scalar value, i.e. a lone surrogate. (If you need to be able to encode non-scalar values as well, use [WTF-8](https://mths.be/wtf8) instead.)
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```js
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// U+00A9 COPYRIGHT SIGN; see http://codepoints.net/U+00A9
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utf8.encode('\xA9');
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// → '\xC2\xA9'
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// U+10001 LINEAR B SYLLABLE B038 E; see http://codepoints.net/U+10001
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utf8.encode('\uD800\uDC01');
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// → '\xF0\x90\x80\x81'
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```
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### `utf8.decode(byteString)`
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Decodes any given UTF-8-encoded string (`byteString`) as UTF-8, and returns the UTF-8-decoded version of the string. It throws an error when malformed UTF-8 is detected. (If you need to be able to decode encoded non-scalar values as well, use [WTF-8](https://mths.be/wtf8) instead.)
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```js
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utf8.decode('\xC2\xA9');
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// → '\xA9'
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utf8.decode('\xF0\x90\x80\x81');
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// → '\uD800\uDC01'
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// → U+10001 LINEAR B SYLLABLE B038 E
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```
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### `utf8.version`
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A string representing the semantic version number.
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## Support
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utf8.js has been tested in at least Chrome 27-39, Firefox 3-34, Safari 4-8, Opera 10-28, IE 6-11, Node.js v0.10.0, Narwhal 0.3.2, RingoJS 0.8-0.11, PhantomJS 1.9.0, and Rhino 1.7RC4.
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## Unit tests & code coverage
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After cloning this repository, run `npm install` to install the dependencies needed for development and testing. You may want to install Istanbul _globally_ using `npm install istanbul -g`.
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Once that’s done, you can run the unit tests in Node using `npm test` or `node tests/tests.js`. To run the tests in Rhino, Ringo, Narwhal, PhantomJS, and web browsers as well, use `grunt test`.
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To generate the code coverage report, use `grunt cover`.
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## FAQ
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### Why is the first release named v2.0.0? Haven’t you heard of [semantic versioning](http://semver.org/)?
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Long before utf8.js was created, the `utf8` module on npm was registered and used by another (slightly buggy) library. @ryanmcgrath was kind enough to give me access to the `utf8` package on npm when I told him about utf8.js. Since there has already been a v1.0.0 release of the old library, and to avoid breaking backwards compatibility with projects that rely on the `utf8` npm package, I decided the tag the first release of utf8.js as v2.0.0 and take it from there.
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## Author
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| [](https://twitter.com/mathias "Follow @mathias on Twitter") |
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| [Mathias Bynens](https://mathiasbynens.be/) |
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## License
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utf8.js is available under the [MIT](https://mths.be/mit) license.
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