msgpackr

msgpackr is an extremely fast MessagePack NodeJS/JavaScript implementation. At the time of writing, it is several times faster than any other known implementations, faster than Avro (for JS), and generally even faster than native JSON.stringify/parse. It also includes an optional record extension, for defining record structures that makes MessagePack even faster and more compact, often over twice as fast as even native JSON methods and many times faster any other JS implementations.

Basic Usage

Install with:

npm install msgpackr

And import or require it for basic unpack and pack functions:

import { unpack, pack } from 'msgpackr';
let packdAsBuffer = pack(value);
let data = unpack(packdAsBuffer);

This pack function will generate standard MessagePack without any extensions that should be compatible with any standard MessagePack serializer. It will pack JavaScript objects as MessagePack maps by default. The unpack function will deserialize MessagePack maps as an Object with the properties from the map.

Record / Object Structures

There is a critical difference between maps (or dictionaries) that hold an arbitrary set of keys and values, and records or object structures that have a well-defined set of fields which may have many instances using that same structure. By using the record extension, this distinction is preserved in MessagePack and the encoding can reuse structures and not only provides better type preservation, but yield signficantly more compact encodings and increase parsing/deserialization performance by 2-3x. msgpackr automatically generates record definitions that are reused and referenced by objects with the same structure. There are a number of ways to use this to our advantage. For large object structures with repeating nested objects with similar structures, simply serializing with the record extension can yield benefits. To use the record structures extension, we create a new Packr instance. By default a new Packr instance will have the record extension enabled:

import { Packr } from 'msgpackr';
let packr = Packr();
packr.pack(myBigData);

Another way to further leverage the benefits of the msgpackr record structures is to use streams that naturally allow for data to reuse based on previous record structures. We can use the PackrStream instance that will have also the record extension enabled by default:

import { PackrStream } from 'msgpackr';
let stream = PackrStream();
stream.write(myData);

Or for a full example of sending and receiving data on a stream

import { PackrStream } from 'msgpackr';
let stream1 = PackrStream();
let stream2 = PackrStream();
stream1.pipe(stream2); // we just piping to our own stream, but normally you would send and receive over some type of inter-process or network connection.
stream1.write(myData);
stream2.on('data', (data) => {
    // received data
}

When creating a new Packr or PackrStream instance, we can enable or disable the record structure extension with the objectsAsMaps property. When this is true, the record structure extension will be disabled, and all objects will be serialized using MessageMap maps, and all maps will be deserialized to JS Objects as properties.

Shared Record Structures

Another valuable way of using msgpackr record extension is for storing data, such as in a database or in files. If a number of objects with common data structures, are being stored, a shared structure can be used to greatly improve data storage and deserialization efficiency. We just need to provide a way to store the generated shared structure so it is available to deserialize stored data in the future:

import { Packr } from 'msgpackr';
let packr = Packr({
    getStructures() {
        // storing our data in file (but we could also store in a db or key-value store)
        return unpack(readFileSync('my-shared-structures.mp')) || [];
    },
    saveStructures(structures) {
        writeFileSync('my-shared-structures.mp', pack(structures))
    },
    structures: []
});

resetMemory

During the serialization process, data is written to buffers. Allocating new buffers is a relatively expensive process, and the resetMemory method can help allow reuse of buffers that will further improve performance. The resetMemory method can be called when previously created buffer(s) are no longer needed. For example, if we serialized an object, and wrote it to a database, we could indicate that we are done:

let buffer = packr.pack(data);
writeToStorageSync(buffer);
// finished with buffer, we can reset the memory on our packr now:
packr.resetMemory()
// future serialization can now reuse memory for better performance