pako
    DefinitelyTyped icon, indicating that this package has TypeScript declarations provided by the separate @types/pako package

    0.2.9 • Public • Published

    pako - zlib port to javascript, very fast!

    Build Status NPM version

    Why pako is cool:

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

    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!

    Famous projects, using pako:

    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 partialy afferted by marshling (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.

    Install:

    node.js:

    npm install pako
    

    browser:

    bower install pako
    

    Example & API

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

    var pako = require('pako');
     
    // 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. You can force output to be string with option { to: 'string' }.

    var pako = require('pako');
     
    var test = { my: 'super', puper: [456, 567], awesome: 'pako' };
     
    var binaryString = pako.deflate(JSON.stringify(test), { to: 'string' });
     
    //
    // Here you can do base64 encode, make xhr requests and so on.
    //
     
    var restored = JSON.parse(pako.inflate(binaryString, { to: 'string' }));

    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

    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.

    License

    MIT

    Install

    npm i [email protected]

    Version

    0.2.9

    License

    MIT

    Last publish

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