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112 lines
3.7 KiB
Markdown
112 lines
3.7 KiB
Markdown
1 year ago
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text-encoding
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==============
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This is a polyfill for the [Encoding Living
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Standard](https://encoding.spec.whatwg.org/) API for the Web, allowing
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encoding and decoding of textual data to and from Typed Array buffers
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for binary data in JavaScript.
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By default it adheres to the spec and does not support *encoding* to
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legacy encodings, only *decoding*. It is also implemented to match the
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specification's algorithms, rather than for performance. The intended
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use is within Web pages, so it has no dependency on server frameworks
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or particular module schemes.
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Basic examples and tests are included.
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### Install ###
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There are a few ways you can get and use the `text-encoding` library.
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### HTML Page Usage ###
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Clone the repo and include the files directly:
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```html
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<!-- Required for non-UTF encodings -->
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<script src="encoding-indexes.js"></script>
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<script src="encoding.js"></script>
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```
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This is the only use case the developer cares about. If you want those
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fancy module and/or package manager things that are popular these days
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you should probably use a different library.
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#### Package Managers ####
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The package is published to **npm** and **bower** as `text-encoding`.
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Use through these is not really supported, since they aren't used by
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the developer of the library. Using `require()` in interesting ways
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probably breaks. Patches welcome, as long as they don't break the
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basic use of the files via `<script>`.
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### API Overview ###
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Basic Usage
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```js
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var uint8array = new TextEncoder().encode(string);
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var string = new TextDecoder(encoding).decode(uint8array);
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```
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Streaming Decode
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```js
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var string = "", decoder = new TextDecoder(encoding), buffer;
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while (buffer = next_chunk()) {
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string += decoder.decode(buffer, {stream:true});
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}
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string += decoder.decode(); // finish the stream
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```
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### Encodings ###
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All encodings from the Encoding specification are supported:
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utf-8 ibm866 iso-8859-2 iso-8859-3 iso-8859-4 iso-8859-5 iso-8859-6
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iso-8859-7 iso-8859-8 iso-8859-8-i iso-8859-10 iso-8859-13 iso-8859-14
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iso-8859-15 iso-8859-16 koi8-r koi8-u macintosh windows-874
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windows-1250 windows-1251 windows-1252 windows-1253 windows-1254
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windows-1255 windows-1256 windows-1257 windows-1258 x-mac-cyrillic
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gb18030 hz-gb-2312 big5 euc-jp iso-2022-jp shift_jis euc-kr
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replacement utf-16be utf-16le x-user-defined
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(Some encodings may be supported under other names, e.g. ascii,
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iso-8859-1, etc. See [Encoding](https://encoding.spec.whatwg.org/) for
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additional labels for each encoding.)
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Encodings other than **utf-8**, **utf-16le** and **utf-16be** require
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an additional `encoding-indexes.js` file to be included. It is rather
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large (596kB uncompressed, 188kB gzipped); portions may be deleted if
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support for some encodings is not required.
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### Non-Standard Behavior ###
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As required by the specification, only encoding to **utf-8** is
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supported. If you want to try it out, you can force a non-standard
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behavior by passing the `NONSTANDARD_allowLegacyEncoding` option to
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TextEncoder and a label. For example:
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```js
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var uint8array = new TextEncoder(
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'windows-1252', { NONSTANDARD_allowLegacyEncoding: true }).encode(text);
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```
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But note that the above won't work if you're using the polyfill in a
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browser that natively supports the TextEncoder API natively, since the
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polyfill won't be used!
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You can force the polyfill to be used by using this before the polyfill:
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```html
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<script>
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window.TextEncoder = window.TextDecoder = null;
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</script>
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```
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To support the legacy encodings (which may be stateful), the
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TextEncoder `encode()` method accepts an optional dictionary and
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`stream` option, e.g. `encoder.encode(string, {stream: true});` This
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is not needed for standard encoding since the input is always in
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complete code points.
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