@ash.ts/ash

A Typescript port of Ash Framework, an entity framework for game development by Richard Lord. This is the bundle package containing the following packages:

• core - Core module.
• fsm - Finite State Machine for Engine and Entities.
• io - Serialization/Deserialization for Engine.
• signals - Signals used for internal communication.
• tick - Tick providers.
• tools - Optional tools for use with Ash.

Instalation

Using npm:

npm i @ash.ts/ash

Using yarn:

yarn add @ash.ts/ash

Examples

• Asteroids (SVG version): Demo Source
• Asteroids (PIXI.js version): Demo Source

Documentation

TypeDoc generated API docs

Richard Lord also written a few blog posts explaining how Ash works.

• Ash - a new entity framework for Actionscript games.
• What is an entity framework for game development.
• Why use an entity framework for game development.

Join the discussion (for AS3 version)

There is a Google group for discussing Ash, how to use it and how to make it better. Everyone who uses Ash or is interested in using Ash is welcome.

Differences between typescript and AS3 version

As this is a port to a different language there are some changes to the API.

Nodes

Javascript which is a language that typescript is compiling to, is dynamic. Variables that are declared but not yet instantiated doesn't have a type. In AS3 when Node fields are null but they are declared as some type, that information is kept at runtime. Adding typescript to javascript gave us code completion and type checking, but information about type is dropped as soon as code is compiled to javascript and not available at runtime. All you need to add is @keep(Class) to each field of your node. This way type information is available in compile and runtime. Example:

import { Node, keep } from '@ash.ts/ash';
import { Motion, Position } from '../components';

export class MovementNode extends Node {
 
 @keep(Position)
 public position!:Position;
 
 @keep(Motion)
 public motion!:Motion;
 
}

Exclamation mark used in this example is a non-null assertion operator. If you use "strict": true or "strictNullChecks": true flags in your tsconfig.json file, it's the way to silent compiler. You as a developer can guarantee that these values will never be null, because as soon as they are created by the Engine they are filled with components.

Systems

Base System class is declared as abstract class with these methods marked as required to be declared in an inherited class.

• public abstract addToEngine(engine:Engine):void;
• public abstract removeFromEngine(engine:Engine):void;
• public abstract update(time:number):void;

Example usage:

import { Engine, NodeList, System } from '@ash.ts/ash';
import { RenderNode } from '../nodes';

export class RenderSystem extends System {
  private nodes:NodeList<RenderNode> | null = null;

  constructor(public container:HTMLElement) {
    super();
  }

  public addToEngine(engine:Engine):void {
    this.nodes = engine.getNodeList(RenderNode);
    // some more logic
  }

  public update(time:number):void {
    for (let node = this.nodes!.head; node; node = node.next) {
      // update logic
    }
  }

  public removeFromEngine(engine:Engine):void {
    this.nodes = null;
    // some more logic
  }
}

IO

This package provides (de)serialization of Engine. Because of how js handle types, you need to provide additional string to ClassType map. Eg.:

import { JsonEngineCodec } from '@ash.ts/io';
import { Display, Position } from '../components';

const classMap = new Map();
classMap.set('Position', Position);
classMap.set('Display', Display);
// ... add other classes

const codec = new JsonEngineCodec(classMap);

Other way to create Map (array of [string, ClassType] tuples):

const classMap = new Map([
  ['Position', Position],
  ['Display', Display],
  // ... other classes
]);

If you export all components in one file, you can use this method:

import * as components from './components';

const map = new Map(
  Object
    .keys(components)
    .map(key => [key, components[key as keyof typeof components]])
);

If your components are more complex objects, remember to also add all used Classes. Eg. if you use PIXI you might want to add DisplayObject class.

map.set('PIXI.DisplayObject', PIXI.DisplayObject);

Second important difference is exported JSON format. It's similar but not the same. All object codecs return object that implements EncodedObject interface. All use the same "value" key. AS3 version use different keys for different types.

Typescript exported json example:

{
  "id": 1,
  "type": "Position",
  "value": ...
}

value can be any valid json, eg. array in ArrayObjectCodec, number, boolean or string in NativeObjectCodec or object in most other codecs.

ListIteratingSystem

This utility class is also declared as abstract class with updateNode method marked as required. There are also 2 optional callback methods that can be declared in an inherited class:

• protected nodeAdded?:(node:Node) => void;
• protected nodeRemoved?:(node:Node) => void;

Example usage:

import { ListIteratingSystem } from '@ash.ts/ash';
import { MovementNode } from '../nodes';

export class MovementSystem extends ListIteratingSystem<MovementNode> {
  constructor() {
    super(MovementNode);
  }

  // required
  public updateNode(node:MovementNode, time:number):void {
    // update logic
  }
  
  // optional
  public nodeAdded = (node:MovementNode) => {
    // logic to execute when new node is added to the system
  };
  
  // optional
  public nodeRemoved = (node:MovementNode) => {
    // logic to execute when new node is removed from the system
  };
}

Alternatives

These are alternative typescript ports you can find:

• ash-ts - Private source code. No docs, no examples, only core module. Components must inherit from the AshComponent class.
• AshTS - Not a node module, core package only.