Test if a value is a gzip buffer.
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> Test if a value is a [gzip][gzip-rfc-1952] buffer.
``bash`
npm install @stdlib/assert-is-gzip-buffer
`javascript`
var isgzipBuffer = require( '@stdlib/assert-is-gzip-buffer' );
#### isgzipBuffer( value )
Tests if a value is a [gzip][gzip-rfc-1952] buffer.
`javascript
var Uint8Array = require( '@stdlib/array-uint8' );
var buf = new Uint8Array( 20 );
buf[ 0 ] = 31; // 0x1f => magic number
buf[ 1 ] = 139; // 0x8b
buf[ 2 ] = 8; // 0x08 => compression method
var bool = isgzipBuffer( buf );
// returns true
bool = isgzipBuffer( [] );
// returns false
`
- A [gzip][gzip-rfc-1952] buffer is defined as either a Node.js [Buffer][@stdlib/buffer/ctor] or [Uint8Array][@stdlib/array/uint8] which contains a 10-byte header, a body containing the compressed payload, and an 8-byte footer containing a CRC-32 checksum and the length of the original uncompressed data, modulo 2^32.
- This function only examines the 10-byte header to ensure the header includes the expected magic number and compression method. The function does not perform an integrity check.
`javascript
var Float32Array = require( '@stdlib/array-float32' );
var Float64Array = require( '@stdlib/array-float64' );
var Int8Array = require( '@stdlib/array-int8' );
var Int16Array = require( '@stdlib/array-int16' );
var Int32Array = require( '@stdlib/array-int32' );
var Uint8Array = require( '@stdlib/array-uint8' );
var Uint8ClampedArray = require( '@stdlib/array-uint8c' );
var Uint16Array = require( '@stdlib/array-uint16' );
var Uint32Array = require( '@stdlib/array-uint32' );
var isgzipBuffer = require( '@stdlib/assert-is-gzip-buffer' );
var buf = new Uint8Array( 20 );
buf[ 0 ] = 31; // 0x1f => magic number
buf[ 1 ] = 139; // 0x8b
buf[ 2 ] = 8; // 0x08 => compression method
var bool = isgzipBuffer( buf );
// returns true
bool = isgzipBuffer( new Float32Array( 20 ) );
// returns false
bool = isgzipBuffer( new Int8Array( 20 ) );
// returns false
bool = isgzipBuffer( new Uint8Array( 20 ) );
// returns false
bool = isgzipBuffer( new Uint8ClampedArray( 20 ) );
// returns false
bool = isgzipBuffer( new Int16Array( 20 ) );
// returns false
bool = isgzipBuffer( new Uint16Array( 20 ) );
// returns false
bool = isgzipBuffer( new Int32Array( 20 ) );
// returns false
bool = isgzipBuffer( new Uint32Array( 20 ) );
// returns false
bool = isgzipBuffer( new Float64Array( 20 ) );
// returns false
bool = isgzipBuffer( new Array( 20 ) );
// returns false
bool = isgzipBuffer( {} );
// returns false
bool = isgzipBuffer( null );
// returns false
`
*
- [@stdlib/assert-is-buffer][@stdlib/assert/is-buffer]: test if a value is a Buffer object.
- [@stdlib/assert-is-uint8array][@stdlib/assert/is-uint8array]: test if a value is a Uint8Array.
*
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
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---
See [LICENSE][stdlib-license].
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
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[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/assert-is-gzip-buffer/tree/deno
[deno-readme]: https://github.com/stdlib-js/assert-is-gzip-buffer/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/assert-is-gzip-buffer/tree/umd
[umd-readme]: https://github.com/stdlib-js/assert-is-gzip-buffer/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/assert-is-gzip-buffer/tree/esm
[esm-readme]: https://github.com/stdlib-js/assert-is-gzip-buffer/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/assert-is-gzip-buffer/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/assert-is-gzip-buffer/main/LICENSE
[gzip-rfc-1952]: https://tools.ietf.org/html/rfc1952
[@stdlib/buffer/ctor]: https://www.npmjs.com/package/@stdlib/buffer-ctor
[@stdlib/array/uint8]: https://www.npmjs.com/package/@stdlib/array-uint8
[@stdlib/assert/is-buffer]: https://www.npmjs.com/package/@stdlib/assert-is-buffer
[@stdlib/assert/is-uint8array]: https://www.npmjs.com/package/@stdlib/assert-is-uint8array