pako

zlib port to javascript, very fast!

Why pako is cool:

• Results are binary equal to well known zlib (now contains ported zlib v1.2.8).
• Almost as fast in modern JS engines as C implementation (see benchmarks).
• Works in browsers, you can browserify any separate component.

This project was done to understand how fast JS can be and is it necessary to develop native C modules for CPU-intensive tasks. Enjoy the result!

Benchmarks:

node v0.10.26, 1mb sample:

   deflate-dankogai x 4.73 ops/sec ±0.82% (15 runs sampled)
   deflate-gildas x 4.58 ops/sec ±2.33% (15 runs sampled)
   deflate-imaya x 3.22 ops/sec ±3.95% (12 runs sampled)
 ! deflate-pako x 6.99 ops/sec ±0.51% (21 runs sampled)
   deflate-pako-string x 5.89 ops/sec ±0.77% (18 runs sampled)
   deflate-pako-untyped x 4.39 ops/sec ±1.58% (14 runs sampled)
 * deflate-zlib x 14.71 ops/sec ±4.23% (59 runs sampled)
   inflate-dankogai x 32.16 ops/sec ±0.13% (56 runs sampled)
   inflate-imaya x 30.35 ops/sec ±0.92% (53 runs sampled)
 ! inflate-pako x 69.89 ops/sec ±1.46% (71 runs sampled)
   inflate-pako-string x 19.22 ops/sec ±1.86% (49 runs sampled)
   inflate-pako-untyped x 17.19 ops/sec ±0.85% (32 runs sampled)
 * inflate-zlib x 70.03 ops/sec ±1.64% (81 runs sampled)

node v0.11.12, 1mb sample:

   deflate-dankogai x 5.60 ops/sec ±0.49% (17 runs sampled)
   deflate-gildas x 5.06 ops/sec ±6.00% (16 runs sampled)
   deflate-imaya x 3.52 ops/sec ±3.71% (13 runs sampled)
 ! deflate-pako x 11.52 ops/sec ±0.22% (32 runs sampled)
   deflate-pako-string x 9.53 ops/sec ±1.12% (27 runs sampled)
   deflate-pako-untyped x 5.44 ops/sec ±0.72% (17 runs sampled)
 * deflate-zlib x 14.05 ops/sec ±3.34% (63 runs sampled)
   inflate-dankogai x 42.19 ops/sec ±0.09% (56 runs sampled)
   inflate-imaya x 79.68 ops/sec ±1.07% (68 runs sampled)
 ! inflate-pako x 97.52 ops/sec ±0.83% (80 runs sampled)
   inflate-pako-string x 45.19 ops/sec ±1.69% (57 runs sampled)
   inflate-pako-untyped x 24.35 ops/sec ±2.59% (40 runs sampled)
 * inflate-zlib x 60.32 ops/sec ±1.36% (69 runs sampled)

zlib's test is partially affected by marshalling (that make sense for inflate only). You can change deflate level to 0 in benchmark source, to investigate details. For deflate level 6 results can be considered as correct.

Example & API

Full docs - http://nodeca.github.io/pako/

import pako from "https://raw.githubusercontent.com/Denocord/pako/master/mod.js";
// or
import { deflate, inflate, Inflate } from "https://raw.githubusercontent.com/Denocord/pako/master/mod.js";

// Deflate
//
var input = new Uint8Array();
//... fill input data here
var output = pako.deflate(input);

// Inflate (simple wrapper can throw exception on broken stream)
//
var compressed = new Uint8Array();
//... fill data to uncompress here
try {
  var result = pako.inflate(compressed);
} catch (err) {
  console.log(err);
}

//
// Alternate interface for chunking & without exceptions
//

var inflator = new pako.Inflate();

inflator.push(chunk1, false);
inflator.push(chunk2, false);
...
inflator.push(chunkN, true); // true -> last chunk

if (inflator.err) {
  console.log(inflator.msg);
}

var output = inflator.result;

Sometime you can wish to work with strings. For example, to send big objects as json to server. Pako detects input data type.

import pako from "https://raw.githubusercontent.com/Denocord/pako/master/mod.js";

var test = { my: 'super', puper: [456, 567], awesome: 'pako' };

var data = pako.deflate(JSON.stringify(test));

//
// Here you can do base64 encode, make xhr requests and so on.
//

var restored = JSON.parse(new TextDecoder().decode(pako.inflate(data)));

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. Those should work: Z_NO_FLUSH, Z_FINISH, Z_SYNC_FLUSH.

Authors

• TTtie @TTtie - Deno port
• Andrey Tupitsin @anrd83
• Vitaly Puzrin @puzrin

Personal thanks to:

• Vyacheslav Egorov (@mraleph) for his awesome tutorials about optimising JS code for v8, IRHydra tool and his advices.
• David Duponchel (@dduponchel) for help with testing.

Original implementation (in C):

• zlib by Jean-loup Gailly and Mark Adler.

License

• MIT - all files, except /lib/zlib folder
• ZLIB - /lib/zlib content