rad-ecs

An Entity Component System (ECS) library written in TypeScript, bare bones and easy to use.

Features

This library is heavy on entity creation and management, while being very light on the S (System) part of ECS. What is provided here is a robust entity manager with strong abilities for creation and manipulation of component based entities.

• Entity management
  • Generic creation of entities composed of components
  • Callback based iteration of entities based on component presence
  • Rxjs based event signalling to monitor entity and component changes
  • Indexing by component type to allow quick lookup of all components with a given value e.g get all entities with a position
  • Immutable pattern for updating entities
  • Serialisation of entity data for saving state

Hello world

Simple example showing basic component definition, entity creation and access.

import { EntityManager, Component, Entity } from 'rad-ecs';

class HelloWorld extends Component {
  constructor(
    public message: string = "Hello world!"
  ) {
    super();
  }
}

const helloEm = new EntityManager();
const helloEntity = helloEm.createEntity(new HelloWorld());

console.log(`-- Hello World --`);
console.log(helloEm.get(helloEntity.id).component(HelloWorld).message);

Entity iteration based on component

Shows how to iterate all entities that exist with a given component, or set of components.

enum ShapeType {
  CIRCLE = 'circle',
  SQUARE = 'square',
  TRIANGLE = 'triangle'
}

class Shape extends Component {
  constructor(
    public type: ShapeType
  ) {
    super();
  }
}

class Physical extends Component {
  constructor(
    public weight: number,
    public volume: number
  ) {
    super();
  }
}

const em = new EntityManager();

const newEnt = em.createEntity(
  new Shape(ShapeType.TRIANGLE),
  new Physical(10, 100)
);

em.createEntity(
  new Shape(ShapeType.SQUARE)
);

em.createEntity(
  new Physical(1, 5)
);

console.log(`-- Has Shape --`);
em.each( (e: Entity, s: Shape) => {
  console.log(`Entity: ${e.id}, Shape: ${s.type}`);
}, Shape);

console.log(`-- Has Physical --`);
em.each( (e: Entity, p: Physical) => {
  console.log(`Entity: ${e.id}, Physical: weight ${p.weight}, volume: ${p.volume}`);
}, Physical);

console.log(`-- Has Shape & Physical --`);
em.each( (e: Entity, p: Physical, s: Shape) => {
  console.log(`Entity: ${e.id}, Physical: weight ${p.weight}, volume: ${p.volume} - Shape: ${s.type}`);
}, Physical, Shape);