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56 lines
929 B
56 lines
929 B
6 years ago
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# is-jpg [](https://travis-ci.org/sindresorhus/is-jpg)
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> Check if a Buffer/Uint8Array is a [JPEG](http://en.wikipedia.org/wiki/JPEG) image
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Used by [image-type](https://github.com/sindresorhus/image-type).
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## Install
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```sh
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$ npm install --save is-jpg
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```
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## Usage
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##### Node.js
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```js
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var readChunk = require('read-chunk'); // npm install read-chunk
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var isJpg = require('is-jpg');
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var buffer = readChunk.sync('unicorn.jpg', 0, 3);
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isJpg(buffer);
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//=> true
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```
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##### Browser
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```js
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var xhr = new XMLHttpRequest();
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xhr.open('GET', 'unicorn.jpg');
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xhr.responseType = 'arraybuffer';
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xhr.onload = function () {
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isJpg(new Uint8Array(this.response));
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//=> true
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};
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xhr.send();
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```
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## API
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### isJpg(buffer)
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Accepts a Buffer (Node.js) or Uint8Array.
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It only needs the first 3 bytes.
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## License
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MIT © [Sindre Sorhus](http://sindresorhus.com)
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