@javelin/ecs

A TypeScript Entity-Component System (ECS) for Node and web browsers.

Docs

Visit https://javelin.games for documentation, examples, and external resources.

Features

Fast

Entities are organized by their component makeup into Archetypes for quick lookups and iteration. In a small app (10 component types, 10 archetypes, 10 queries), Javelin can iterate ~2.5 million entities per 16ms on a 2GHz Intel i5 processor.

Ergonomic

Define your game's data model using plain old JavaScript objects.

const Transform = {
  x: float64,
  y: float64,
}
const Inventory = {
  bags: arrayOf(arrayOf(uint32)),
}
const world = createWorld()
const entity = world.create(
  component(Transform), // => { x: 0, y: 0 }
  component(Inventory), // => { bags: [] }
)

Use third-party objects as components.

const Mesh = {
  position: {
    x: number,
    y: number,
    z: number,
  },
}
world.create(toComponent(new Three.Mesh(), Mesh))

Intuitive

Query game state using familiar syntax.

const bodies = createQuery(Transform, Velocity)
const physics = () =>
  bodies((e, [t, v]) => {
    t.x += v.x
    t.y += v.y
  })

Powerful

Best practices are built-in with tools like Topics for inter-system messaging.

const commands = createTopic<PhysicsCommand>()
const movement = () =>
  input((e, [input]) => {
    if (input.jump) {
      commands.push(impulse(e, 0, 10))
    }
  })
const physics = () => {
  for (const command of commands) {
    // ...
  }
}

and Effects for handling async code, third-party dependencies, and events.

const render = () => {
  const scene = useScene()
  const model = useLoadGLTF("llama.gltf")

  useMonitor(
    players,
    e => scene.insert(e, model, world.get(e, Transform)),
    e => scene.destroy(e),
  )
}