Package Exports

@geckos.io/typed-array-buffer-schema
@geckos.io/typed-array-buffer-schema/lib/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@geckos.io/typed-array-buffer-schema) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

Typed Array Buffer Schema

A Schema based Object to Buffer converter

Easily convert/compress your JavaScript Objects to Binary Data using a simple to use Schema.

Introduction

Checkout this short introduction video on YouTube!

https://youtu.be/TBd1miOrLPQ

Install

Install from npm.

npm install @geckos.io/typed-array-buffer-schema

Or use the bundled version.

<script src="https://unpkg.com/@geckos.io/typed-array-buffer-schema@1.0.2/bundle/typed-array-buffer-schema.js"></script>
<script>
  const { BufferSchema, Model }  = Schema
  const { uint8, int16, uint16, int64, string8, ...more } Schema
</script>

Snapshot Interpolation

You can easily combine this library with the Snapshot Interpolation library @geckos.io/snapshot-interpolation.

Usage

model.js

import { BufferSchema, Model } from '@geckos.io/typed-array-buffer-schema'
import { uint8, int16, uint16, int64, string8 } from '@geckos.io/typed-array-buffer-schema'

const playerSchema = BufferSchema.schema('player', {
  id: uint8,
  // The length parameter controls the length of a String8 or String16
  name: { type: string8, length: 6 },
  // The digits parameter controls where the decimal point is placed
  // Therefore, it divides the maximum and minimum values by 10^n
  x: { type: int16, digits: 2 },
  y: { type: int16, digits: 2 }
})

const towerSchema = BufferSchema.schema('tower', {
  id: uint8,
  health: uint8,
  team: uint8
})

const mainSchema = BufferSchema.schema('main', {
  time: int64,
  tick: uint16,
  players: [playerSchema],
  towers: [towerSchema]
})

export const mainModel = new Model(mainSchema)

// if you get the error "RangeError: Offset is outside the bounds of the DataView", increase the max. bufferSize.
// default is 8 (8KB).
export const mainModel = new Model(mainSchema, 8)

server.js

import { mainModel } from './model'

const gameState = {
  time: new Date().getTime(),
  tick: 32580,
  players: [
    { id: 0, name: 'Mistin', x: -14.43, y: 47.78 },
    { id: 1, name: 'Coobim', x: 21.85, y: -78.48 }
  ],
  towers: [
    { id: 0, health: 100, team: 0 },
    { id: 1, health: 89, team: 0 },
    { id: 2, health: 45, team: 1 }
  ]
}

const buffer = mainModel.toBuffer(gameState)

// toBuffer() shrunk the byte size from 241 to only 56
// that is -77% compression!
console.log(JSON.stringify(gameState).length) // 241
console.log(buffer.byteLength) // 56

// send the buffer to the client (using geckos.io or any other library)
sendMessage(buffer)

client.js

import { mainModel } from './model'

onMessage(buffer => {
  // access your game state
  const gameState = mainModel.fromBuffer(buffer)
})

Schema ID

Each Schema has an unique ID. To get the Schema ID from the Schema, Model or Buffer, use the helper functions listed below:

// get the schema id
const schemaId = BufferSchema.getIdFromSchema(schema)

// get the id of the top level schema (added via new Schema())
const modelId = BufferSchema.getIdFromModel(model)

// get the id of the top level schema
const bufferId = BufferSchema.getIdFromBuffer(buffer)

DataViews

A list of all supported dataViews

// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays

/** -128 to 127 (1 byte) */
export const int8 = { _type: 'Int8Array', _bytes: 1 }
/** 0 to 255 (1 byte) */
export const uint8 = { _type: 'Uint8Array', _bytes: 1 }

/** -32768 to 32767 (2 bytes) */
export const int16 = { _type: 'Int16Array', _bytes: 2 }
/** 0 to 65535 (2 bytes) */
export const uint16 = { _type: 'Uint16Array', _bytes: 2 }

/** -2147483648 to 2147483647 (4 bytes) */
export const int32 = { _type: 'Int32Array', _bytes: 4 }
/** 0 to 4294967295 (4 bytes) */
export const uint32 = { _type: 'Uint32Array', _bytes: 4 }

/** -2^63 to 2^63-1 (8 bytes) */
export const int64 = { _type: 'BigInt64Array', _bytes: 8 }
/** 0 to 2^64-1 (8 bytes) */
export const uint64 = { _type: 'BigUint64Array', _bytes: 8 }

/** 1.2×10-38 to 3.4×1038 (7 significant digits e.g., 1.123456) (4 bytes) */
export const float32 = { _type: 'Float32Array', _bytes: 4 }

/** 5.0×10-324 to 1.8×10308 (16 significant digits e.g., 1.123...15) (8 bytes) */
export const float64 = { _type: 'Float64Array', _bytes: 8 }

/** 1 byte per character */
export const string8 = { _type: 'String8', _bytes: 1 }
/** 2 bytes per character */
export const string16 = { _type: 'String16', _bytes: 2 }

/** An array of 7 booleans */
export const bool8 = { _type: 'BitArray8', _bytes: 1 }
/** An array of 15 booleans */
export const bool16 = { _type: 'BitArray16', _bytes: 2 }