msgpack.js

This is a MessagePack codec written in JavaScript for web browsers (including IE 11). Support for JavaScript servers like Node.js is unknown because I’m not using those, but I see no reason why it shouldn’t work.

It is compact but still fully-featured. This library supports the complete MessagePack specification released on 2017-08-09, including date/time values. No other extension types are implemented in this library, it’s only the standard types which is perfectly fine for interoperability with MessagePack codecs in other programming languages.

I’m using the MessagePack-CSharp library on the server side in my .NET applications.

MessagePack

MessagePack is an efficient binary serialisation format. It lets you exchange data among multiple languages like JSON. But it’s faster and smaller. Small integers are encoded into a single byte, and typical short strings require only one extra byte in addition to the strings themselves.

Size

This codec is very lightweight. The source code has around 480 lines, the minified file is below 6.5 kB and can be GZip-compressed to 2.2 kB.

Performance

The file msgpack-tests.html contains some tests and a benchmark function that compares this library with msgpack-lite. Here are the results, in milliseconds (lower is better). All tests done on an Intel Core i7-3770 and Windows 10.

Function	Chrome 70		Firefox 63		Edge 16		IE 11
serializeMsgPack	722 ms	+10%	1181 ms	−45%	2739 ms	+50%	2550 ms	−3%
msgpack.encode	659 ms		2138 ms		1829 ms		2617 ms
deserializeMsgPack	647 ms	+11%	773 ms	−3%	816 ms	−49%	634 ms	−66%
msgpack.decode	582 ms		801 ms		1601 ms		1870 ms

The numbers show that this library is comparable with msgpack-lite. In Chrome it’s only 10% slower. But serializing in Firefox and deserializing in Microsoft browsers is twice as fast.

Usage

The source file contains two public functions: serializeMsgPack and deserializeMsgPack. The first can be called with any data and returns the encoded bytes. The second works in reverse, taking the encoded bytes and returning the runtime value.

Here’s a simple example:

// Define some data to encode
var sourceData = {
    number: 123,
    number2: -0.129,
    text: "Abc with Üñıçôðé and ユニコード",
    flag: true,
    list: [ 1, 2, 3 ],
    obj: { a: 1, b: "2", c: false, d: { a: 0, b: -1 } },
    time: Date.now()
};

// Encode to byte array
var encodedBytes = serializeMsgPack(sourceData);

// Decode again
var decodedData = deserializeMsgPack(encodedBytes);

Include the JavaScript file into your HTML document like this:

<script src="msgpack.min.js"></script>

You can use the codec functions after loading the script. No additional configuration required.

License