World

Worlds are responsible for maintaining entities and executing systems. They expose a step() method which moves the world forward in time as well as methods to manage entities and their components.

A world is created using the createWorld function defined in world.ts.

import { createWorld } from "@javelin/ecs"

const world = createWorld()

Systems#

Systems in Javelin are simple functions that can be registered with a world to be executed each tick. They are discussed at length in the Systems section.

There are two ways to register a system with a world. Either use the systems property in the options object passed to createWorld:

createWorld({
  systems: [physics, render],
})

or after a world is created using the world.addSystem() method:

const lazySystem = import("./systems/lazy")
world.addSystem(lazySystem)

Maintenance#

Snapshots#

world.createSnapshot() produces a JSON-serializable snapshot of a world's entities and components. You can use the snapshot to seed a new world with entities later:

const snapshot = worldA.createSnapshot()
const worldB = createWorld({ snapshot })

Reset#

Use world.reset() to completely reset a world. This method will clear all entity data and release components back to their object pool.