BitSparrow in JavaScript

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Encoding

var Encoder = require('bitsparrow').Encoder;

var buffer = new Encoder()
             .uint8(100)
             .string("Foo")
             .end();

console.log(buffer); // Uint8Array | Buffer [0x64,0x03,0x46,0x6f,0x6f]

The type of the buffer used by BitSparrow changes depending on the environment - when used within Node.js it becomes a Buffer, otherwise the more generic Uint8Array is used.

When piping data through a WebSocket in the Browser, set the binary mode to use ArrayBuffer over Blob, and create the Uint8Array view on top of it:

var bitsparrow = require('bitsparrow');

var socket = new WebSocket('ws://example.com/');
socket.binaryType = 'arraybuffer';

socket.onmessage = function(event) {
    let decoder = new bitsparrow.Decoder(new Uint8Array(event.data));
    // Read the data ...
}

socket.onpen = function() {
    let decoder = new bitsparrow.Encoder().string('Hello World');
    // Send internal `ArrayBuffer` from `Uint8Array`
    socket.send(decoder.end().buffer);
}

Each method on the Encoder will consume the instance of the struct. If you need to break the monad chain, store the intermediate state of the encoder, e.g.:

Decoding

var Decoder = require('bitsparrow').Decoder;

var buffer = new Uint8Array([0x64,0x03,0x46,0x6f,0x6f]);
var decoder = new Decoder(buffer);

console.log(decoder.uint8()); // -> 100
console.log(decoder.string()); // -> "Foo"
console.log(decoder.end()); // -> true

Decoder takes a reference to the buffer and allows you to retrieve the values in order they were encoded. Calling the end method is optional, it will return true if you have read the entire buffer, which can be handy if you are reading multiple messages stacked on a single buffer.

Performance

The goal of this library is to reduce both the size and parsing time of data when compared to JSON or msgpack. While JavaScript lacks low level primitive number type transmutations, using pre-cached TypedArrays yields very fast results. You can run benchmarks with:

npm run bench

Most notably, fixed size number decoding, such as float64 and uint32, is much faster than even the native JSON implementation in V8, with time per operation being less than 100 nanoseconds on most (even old) CPUs.

The MIT License (MIT)

Copyright (c) 2016 BitSparrow

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.