typescript-binary v1.6.4

TypeScript Binary

Powerful, lightweight binary messages in TypeScript.

• 🔌 Compatible with geckos.io, socket.io and peer.js.
• 🗜️ Smaller than FlatBuffers or Protocol Buffers.
• 🏋️‍♀️ Support advanced features like property mangling and 16-bit floats.
• ⚡️ Based on the lightning-fast sitegui/js-binary library, written by Guilherme Souza.

📣 When to use?

TypeScript Binary is an optimal choice for real-time HTML5 and Node.js applications and games.

†Based on the Reference data formats and schemas

*When using protobufjs

Sample data (Minified JSON):

{
  "players": [
    {
      "id": 123,
      "position": {
        "x": 1.0,
        "y": 2.0,
        "z": 3.0
      },
      "velocity": {
        "x": 1.0,
        "y": 2.0,
        "z": 3.0
      },
      "health": 1.00
    },
    {
      "id": 456,
      "position": {
        "x": 1.0,
        "y": 2.0,
        "z": 3.0
      },
      "velocity": {
        "x": 1.0,
        "y": 2.0,
        "y": 3.0
      },
      "health": 0.50
    }
  ]
}

TypeScript Binary

const ExampleMessage = new BinaryCoder({
  players: [
    {
      id: Type.UInt,
      position: {
        x: Type.Float16,
        y: Type.Float16,
        z: Type.Float16
      },
      velocity: {
        x: Type.Float16,
        y: Type.Float16,
        y: Type.Float16
      },
      health: Type.UScalar
    },
  ],
});

FlatBuffers

// ExampleMessage.fbs

namespace ExampleNamespace;

table Vec3 {
  x: float;
  y: float;
  z: float;
}

table Player {
  id: uint;
  position: Vec3;
  velocity: Vec3;
  health: float;
}

table ExampleMessage {
  players: [Player];
}

root_type ExampleMessage;

Protocol Buffers (Proto3)

syntax = "proto3";

package example;

message Vec3 {
  float x = 1;
  float y = 2;
  float z = 3;
}

message Player {
  uint32 id = 1;
  Vec3 position = 2;
  Vec3 velocity = 3;
  float health = 4;
}

message ExampleMessage {
  repeated Player players = 1;
}

Install

npm install typescript-binary

yarn add typescript-binary

Usage

Define formats

Create a BinaryCoder like so:

import { BinaryCoder, Type } from "typescript-binary";

// Define your format:
const GameWorldData = new BinaryCoder({
  time: Type.UInt,
  players: [{
    id: Type.UInt,
    isJumping: Type.Boolean,
    position: {
      x: Type.Float,
      y: Type.Float
    }
  }]
});

// Encode:
const bytes = GameWorldData.encode({
  time: 123,
  players: [
    {
       id: 44,
       isJumping: true,  
       position: {
         x: 110.57345,
         y: -93.5366
       }
    }
  ]
});

bytes.byteLength
// 14

// Decode:
const data = GameWorldData.decode(bytes);

Inferred types

BinaryCoder will automatically infer the types for encode() and decode() from the schema provided (see the Types section below).

For example, the type T for GameWorldData.decode(...): T would be inferred as:

{
  timeRemaining: number,
  players: {
    id: string,
    health: number,
    isJumping: boolean,
    position?: {
      x: number,
      y: number
    }
  }[]
}

You can also use the Infer<T> helper type to use inferred types in any custom method/handler:

import { Infer } from "typescript-binary";

function updateGameWorld(data: Infer<typeof GameWorldData>) {
  // e.g. Access `data.players[0].position?.x`
}

✨ Parsing formats

By default, each BinaryCoder encodes a 2-byte identifier based on the shape of the data.

You can explicitly set Id in the BinaryCoder constructor to any 2-byte string or unsigned integer (or disable entirely by passing false).

Use BinaryFormatHandler

Handle multiple binary formats at once using a BinaryFormatHandler:

import { BinaryFormatHandler } from "typescript-binary";

const binaryHandler = new BinaryFormatHandler()
  .on(MyFormatA, (data) => handleMyFormatA(data))
  .on(MyFormatB, (data) => handleMyFormatB(data));

// Trigger handler (or throw UnhandledBinaryDecodeError)
binaryHandler.processBuffer(binary);

Note: Cannot be used with formats where Id is disabled.

Manual handling

You can manually read message identifers from incoming buffers with the static function BinaryCoder.peekIntId(...) (or BinaryCoder.peekStrId(...)):

if (BinaryCoder.peekStrId(incomingBinary) === MyMessageFormat.Id) {
  // Do something special.
}

💥 Id Collisions

By default Id is based on a hash code of the encoding format. So the following two messages would have identical Ids:

const Person = new BinaryCoder({
  firstName: Type.String,
  lastName: Type.String
});

const FavoriteColor = new BinaryCoder({
  fullName: Type.String,
  color: Type.String
});

NameCoder.Id === ColorCoder.Id
  // true

If two identical formats with different handlers is a requirement, you can explicitly set unique identifiers.

const Person = new BinaryCoder({
  firstName: Type.String,
  lastName: Type.String
}, "PE");

const FavoriteColor = new BinaryCoder({
  fullName: Type.String,
  color: Type.String
}, "FC");

✨ Validation / Transforms

Validation

The great thing about binary encoders is that data is implicitly type-validated, however, you can also add custom validation rules using setValidation():

const UserMessage = new BinaryCoder({
  uuid: Type.String,
  // ...
})
.setValidation({
  uuid: (x) => {
    if (!isValidUUIDv4(x)) {
      throw new Error('Invalid UUIDv4: ' + x);
    }
  }
});

Transforms

You can also apply additional encode/decode transforms.

Here is an example where we're stripping out all whitespace:

const PositionMessage = new BinaryCoder({ name: Type.String })
  .setTransforms({ name: a => a.replace(/\s+/g, '') });

let binary = PositionMessage.encode({ name: 'Hello  There' })
let data = PositionMessage.decode(binary);

data.name
  // "HelloThere"

Unlike validation, transforms are applied asymmetrically.

The transform function is only applied on encode(), but you can provide two transform functions.

Here is an example which cuts the number of bytes required from 10 to 5:

const PercentMessage = new BinaryCoder({ value: Type.String }, false)
  .setTransforms({
    value: [
      (before) => before.replace(/\$|USD/g, '').trim(),
      (after) => '$' + after + ' USD'
    ]
  });

let binary = PercentMessage.encode({ value: ' $45.53 USD' })
let data = PercentMessage.decode(binary);

binary.byteLength
  // 5

data.value
  // "$45.53 USD"

Types

Here are all the ready-to-use types:

*Int is a variable-length integer ("varint") which encodes <±64 = 1 byte, <±8,192 = 2 bytes, <±268,435,456 = 4 bytes, otherwise = 8 bytes.

#UInt is a variable-length unsigned integer ("varuint") which encodes <128 = 1 byte, <16,384 = 2 bytes, <536,870,912 = 4 bytes, otherwise = 8 bytes.

†Length of payload bytes as a UInt. Typically 1 byte, but could be 2-8 bytes for very large payloads.

¶2-bit overhead: 6 booleans per byte (i.e. 9 booleans would require 2 bytes).

Encoding guide

See docs/ENCODING.md for an overview on how most formats are encoded (including the dynamically sized integer types).