pako
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zlib port to javascript - fast, modularized, with browser support
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pako
==========================================
[](https://github.com/nodeca/pako/actions)
[](https://www.npmjs.org/package/pako)
> Very fast zlib-compatible compression for JavaScript.
## Why pako is cool
- __Binary-equivalent output.__ Pako can produce the same deflate/gzip bytes as
original [zlib](http://www.zlib.net/) (1.3.2) and Node.js' patched zlib.
- __Tiny browser bundles.__ Full minified bundle is under 15K gzipped.
Deflate-only and inflate-only builds are smaller.
- __Very fast.__ Performance is comparable with native zlib in modern JavaScript
engines (see benchmarks).
## Benchmarks
node v24, 1 MB input sample:
```
deflate-pako x 14.27 ops/sec ±3.41% (37 runs sampled)
deflate-pako-zlib-hash x 10.60 ops/sec ±0.50% (29 runs sampled)
deflate-zlib x 30.30 ops/sec ±0.61% (51 runs sampled)
gzip-pako x 13.48 ops/sec ±0.50% (36 runs sampled)
inflate-pako x 138 ops/sec ±1.26% (75 runs sampled)
inflate-zlib x 397 ops/sec ±1.37% (81 runs sampled)
ungzip-pako x 125 ops/sec ±1.46% (73 runs sampled)
```
## Install
```
npm install pako
```
> [!NOTE]
> For a quick look at `dist/` folder contents, see
> <https://unpkg.com/pako@latest/>.
Examples / API
--------------
Full docs - http://nodeca.github.io/pako/
```javascript
import { Deflate, Inflate, deflate, inflate } from 'pako';
// Deflate
//
const input = new Uint8Array();
//... fill input data here
const output = deflate(input);
// Inflate (simple wrapper can throw exception on broken stream)
//
const compressed = new Uint8Array();
//... fill data to uncompress here
try {
const result = inflate(compressed);
// ... continue processing
} catch (err) {
console.log(err);
}
//
// Alternate interface for chunking & without exceptions
//
const deflator = new Deflate();
deflator.push(chunk1, false);
deflator.push(chunk2); // second param is false by default.
...
deflator.push(chunk_last, true); // `true` says this chunk is last
if (deflator.err) {
console.log(deflator.msg);
}
const output = deflator.result;
const inflator = new Inflate();
inflator.push(chunk1);
inflator.push(chunk2);
...
inflator.push(chunk_last); // no second param because end is auto-detected
if (inflator.err) {
console.log(inflator.msg);
}
const output = inflator.result;
```
For CommonJS:
```javascript
const { deflate, inflate } = require('pako');
```
If you need the whole API as an object, use namespace import:
```javascript
import * as pako from 'pako';
```
Sometimes you may wish to work with strings — for example, to send
stringified objects to a server. Pako's deflate detects the input data type and
automatically recodes strings to utf-8 prior to compression. High-level inflate
helpers can decode utf-8 output back to JavaScript strings with `toText: true`.
```javascript
import { deflate, inflate } from 'pako';
const test = { my: 'super', puper: [456, 567], awesome: 'pako' };
const compressed = deflate(JSON.stringify(test));
const restored = JSON.parse(inflate(compressed, { toText: true }));
```
## Notes
Pako does not contain some specific zlib functions:
- __deflate__ - methods `deflateCopy`, `deflateBound`, `deflateParams`,
`deflatePending`, `deflatePrime`, `deflateTune`.
- __inflate__ - methods `inflateCopy`, `inflateMark`,
`inflatePrime`, `inflateGetDictionary`, `inflateSync`, `inflateSyncPoint`, `inflateUndermine`.
- High level inflate/deflate wrappers (classes) may not support some flush
modes.
## Authors
- Andrey Tupitsin [@anrd83](https://github.com/andr83)
- Vitaly Puzrin [@puzrin](https://github.com/puzrin)
Personal thanks to:
- Vyacheslav Egorov ([@mraleph](https://github.com/mraleph)) for his awesome
tutorials about optimising JS code for v8, [IRHydra](http://mrale.ph/irhydra/)
tool and his advices.
- David Duponchel ([@dduponchel](https://github.com/dduponchel)) for help with
testing.
Original implementation (in C):
- [zlib](http://zlib.net/) by Jean-loup Gailly and Mark Adler.
## License
- MIT - all files, except `/src/zlib` folder
- ZLIB - `/src/zlib` content