bitecs

👾 bitECS 👾

Functional, tiny, data-oriented, high performance ECS library written using JavaScript TypedArrays.

Features

• Functional
• <3kb gzipped
• Zero dependencies
• Node or Browser
• Killer performance

Install

npm i bitecs

Example

import { 
  createWorld,
  registerComponent,
  registerComponents,
  defineComponent,
  defineQuery,
  enterQuery,
  exitQuery,
  defineSystem,
  addComponent,
  removeComponent,
  addEntity,
  removeEntity,
  pipe,
  Types,
} from 'bitecs'

// create a world
const world = createWorld()

// define component data stores
const { f32 } = Types
const Vector2 = { x: f32, y: f32 }
const Position = defineComponent(Vector2)
const Velocity = defineComponent(Vector2)
const Health = defineComponent(f32)
const Alive = defineComponent() // "tag" component

// register components on world
registerComponents(world, [Position, Velocity, Health]) // in groups
registerComponent(world, Alive) // or individually

// define a query using components
const movementQuery = defineQuery([Position, Velocity])

// enter-query hook, called when an entity's components matches the query
enterQuery(world, movementQuery, eid => {})

// exit-query hook, called when an entity's components no longer matches the query
exitQuery(world, movementQuery, eid => {})

// define a system using the query
const movementSystem = defineSystem(movementQuery, ents => {
  for (let i = 0; i < ents.length; i++) {
    const eid = ents[i];
    Position.x[eid] += Velocity.x[eid]
    Position.y[eid] += Velocity.y[eid]
  }
})

// add an entity to the world
const eid = addEntity(world)

// add components to the new entity in the world
addComponent(world, Position, eid)
addComponent(world, Velocity, eid)

// there are no component getters or setters
// data is accessed directly by entity ID
Velocity.x[eid] = 1
Velocity.y[eid] = 2

const pipeline = pipe(
  movementSystem,
  movementSystem,
  movementSystem,
)

movementSystem(world) // executes movement system on world
pipeline(world) // executes a pipeline of systems on world

Full documentation and feature rich examples can be found here.