Archetype ECS Lib

A tiny archetype based ECS (Entity Component System) for TypeScript.

This documentation is split into 4 parts :

• Explanation of the general operation of the library
• Find information in the Reference
• Target a specific goal using the How-To Guides
• Learn through the Tutorials: step-by-step guidance

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Install

NPM package available here

npm i archetype-ecs-lib

Quick start

import { World, Schedule } from "archetype-ecs-lib";

class Position { constructor(public x = 0, public y = 0) {} }
class Velocity { constructor(public x = 0, public y = 0) {} }

const world = new World();

// Spawn immediately
const e = world.spawn();
world.add(e, Position, new Position(0, 0));
world.add(e, Velocity, new Velocity(1, 0));

// A simple system
world.addSystem((w) => {
  for (const { e, c1: pos, c2: vel } of w.query(Position, Velocity)) {
    pos.x += vel.x * dt;
    pos.y += vel.y * dt;

    // Defer structural changes safely
    if (pos.x > 10) w.cmd().despawn(e);
  }
});

world.update(1 / 60);

Note: SystemFn is typed as (world: WorldApi, dt) => void.
Checkout the tutorials for more!

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Notes & limitations

• This is intentionally minimal: no parallelism, no borrow-checking, no automatic conflict detection.
• Query results use c1/c2/... fields for stability and speed; you can wrap this in helpers if you prefer tuple returns.
• TypeId assignment is process-local and based on constructor identity (WeakMap).

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License

This code is distributed under the terms and conditions of the MIT license.