npm package: @iceprod/js-binary
Description: Encode/decode to a custom binary format, much more compact and faster than JSON/BSON
Author: Daniel Bulant
Latest version: 1.2.2

# JS Binary

Encode/decode to a custom binary format, much more compact and faster than JSON/BSON. Now with safe `Buffer`s and with typescript type definitions. Also allows to pass custom Buffer class to be used (allows browser usage). Everything else remains compatible with the original `js-binary` package (meaning you can encode with this library and decode with `js-binary` and vice-versa).

## Install

`npm install @iceprod/js-binary`

## Goal

This module is analogous to `JSON.stringify` and `JSON.parse`, but instead of a JSON string, the data is encoded to a custom binary format (using a Buffer instance to store the data).
This format was designed to be very _compact_ and give support for _more types_ (like Date and Buffer).

To reduce overhead in the format, it carries no information about types. This implies that you must define the data schema to encode/decode properly. Huge plus: this automatically validates the data against the given schema (_input sanitization for free!_). This binary format is well suited for very regular data, like API input/output.

Note that, since it's a binary format, it was not meant to be easily viewed/edited by hand.

## Usage

```js
var user = {
  name: {
    first: "Guilherme",
    last: "Souza",
  },
  pass: new Buffer("042697a30b2dafbdf91bf66bdacdcba8", "hex"),
  creationDate: new Date("2014-04-11T21:22:32.504Z"),
  active: true,
  achievements: [3, 14, 15, 92, 65, 35],
};

var Type = require("js-binary").Type;
var schema = new Type({
  name: {
    first: "string",
    last: "string",
  },
  pass: "Buffer",
  creationDate: "date",
  active: "boolean",
  achievements: ["uint"],
  "optionalField?": "int",
});

var encoded = schema.encode(user);

var decoded = schema.decode(encoded);
```

## Benchmark

A quick example:

```json
{
  "name": "js-binary",
  "published": "2014-12-21T23:42:46.558Z",
  "downloads": 1717
}
```

(76 bytes, without formatting) versus `096a732d62696e617279e000014a6f3b531e86b5` (20 bytes)

On average, a 2x to 3x space reduction can be observed.

In the `benchmark` you can find another test with more data. In my machine with node 8.9.0, this is the result:

```plaintext
Encode
        JSON
                Time: 2.47ms
                Size: 190KiB
        js-binary
                Time: 1.453ms (-41%)
                Size: 51KiB (3.7x less)
Decode
        JSON
                Time: 2.791ms
        js-binary
                Time: 0.497ms (-82%)
```

## Available types

### Basic types

- 'uint': unsigned integer (between 0 and 2^53)
- 'int': signed integer (between -2^53 and 2^53)
- 'float': a 64-bit floating-point (the JavaScript number type)
- 'string': a utf-8 string
- 'Buffer': a Buffer instance
- 'boolean': a boolean
- 'regex': a JS RegExp instance
- 'date': a JS Date instance
- 'json': any data supported by [JSON format](http://json.org/). Read bellow for more
- 'oid': mongodb ObjectId (see bellow)

### Compound types

A compound type is an object with (optional) fields. Those fields may be arrays, but with the restriction that every element has the same data schema.

Examples:

- Nested fields: `{a: {b: 'int', d: {e: 'int'}}}`
- Optional fields: `{a: 'int', 'b?': 'int', 'c?': {d: 'int'}}`
- Array fields: `{a: ['int']}`
- All together now: `{'a?': [{'b?': 'int'}]}`

### Array type

An array type in which every element has the same data schema.

Examples:

- Int array: `['int']`
- Object array: `[{v: 'int', f: 'string'}]`

### JSON type

As stated before, the js-binary requires the data to have a rather strict schema. But sometimes, part of the data may not fit this reality. In this case, you can fallback to JSON :)

Of course, a JSON field will miss the point about space efficiency and data validation, but will gain in flexibility.

### ObjectId type

js-binary gives first-class support for mongodb ObjectId. But since js-binary doesn't (and shouldn't) depend on any peculiar mongodb driver, the rules for this type are:

- Encoding: any object `o` is accepted, as long `new Buffer(String(o), 'hex')` yields a 12-byte Buffer
- Decoding: returns a 24-char hex-encoded string

This should be compatible with most ObjectId implementations on the wild

## Spec

The binary format spec is documented in the format.md file