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• About
• Status
• Installation
• Dependencies
• Usage examples
• API
  • Basic usage
• Authors
• License

About

Entity Component System based around typed arrays & sparse sets.

• Entities are merely numeric identifiers
• Component types:
  • Numeric / vectors are stored as typed array views with customizable striding
  • arbitrary JS values are stored in vanilla JS arrays
• Component grouping w/ optional group ownership to allow re-ordering components for optimized iteration
• Systems are plain functions
• Configurable caching of component views: LRU, Unbounded, Null (no-cache)

Status

ALPHA - bleeding edge / work-in-progress

Search or submit any issues for this package

Installation

yarn add @thi.ng/ecs

ESM import:

import * as ecs from "@thi.ng/ecs";

Browser ESM import:

<script type="module" src="https://esm.run/@thi.ng/ecs"></script>

JSDelivr documentation

For Node.js REPL:

const ecs = await import("@thi.ng/ecs");

Package sizes (brotli'd, pre-treeshake): ESM: 3.17 KB

Dependencies

• @thi.ng/api
• @thi.ng/associative
• @thi.ng/binary
• @thi.ng/checks
• @thi.ng/dcons
• @thi.ng/errors
• @thi.ng/idgen
• @thi.ng/logger
• @thi.ng/malloc
• @thi.ng/transducers

Note: @thi.ng/api is in most cases a type-only import (not used at runtime)

Usage examples

One project in this repo's /examples directory is using this package:

| Screenshot | Description | Live demo | Source | |:--------------------------------------------------------------------------------------------------------------------|:---------------------------------------------|:----------------------------------------------|:---------------------------------------------------------------------------| | | Entity Component System w/ 100k 3D particles | Demo | Source |

API

Generated API docs

Basic usage

import { ECS } from "@thi.ng/ecs";

interface CompSpecs {
    pos: Float32Array;
    vel: Float32Array;
    color: string;
}

// init ECS w/ given max number of entities
const ecs = new ECS<CompSpecs>({ capacity: 1000 });

// define components (and their memory layout)
const pos = ecs.defComponent({
    id: "pos",
    type: "f32",
    size: 2,
})!;

const vel = ecs.defComponent({
    id: "vel",
    type: "f32",
    size: 2,
    stride: 4,
    default: () => [Math.random() * 2 - 1, Math.random() * 2 - 1],
})!;

// this component stores string values (not mem-mapped)
const color = ecs.defComponent({
    id: "color",
    default: () => ["red", "green", "blue"][(Math.random() * 3) | 0],
})!;

// define group of given components
// the group will obtain ownership of all by default, meaning
// it is allowed to re-order entities to optimize iteration performance
const group = ecs.defGroup([pos, vel, color]);

// add entities and associate them w/ different components
// if a component is part of a group, the group will be notified/updated
// entities are just numeric IDs assigned using the ECS's internal ID generator
console.log(ecs.defEntity(["pos", "vel", "color"]));
// 0

console.log(ecs.defEntity([pos, vel]));
// 1

console.log(
    ecs.defEntity({
        pos: new Float32Array([1, 2]),
        vel: new Float32Array([-1, 0]),
        color: "orange",
    })
);
// 2

// apply given function to each entity in the group
// note: entity (id=1) is NOT part of the group,
// since it doesn't have a `color` component...
group.forEach((x) => console.log(x));

// Note: The `color` and `vel`ocity of this first item are randomly assigned
// (see component default methods above)

// {
//   id: 0,
//   color: 'green',
//   vel: Float32Array [ 0.16836269199848175, -0.36699679493904114 ],
//   pos: Float32Array [ 0, 0 ]
// }

// {
//   id: 2,
//   color: "orange",
//   vel: Float32Array(2) [ -1, 0 ],
//   pos: Float32Array(2) [ 1, 2 ],
// }

Authors

• Karsten Schmidt

If this project contributes to an academic publication, please cite it as:

@misc{thing-ecs,
  title = "@thi.ng/ecs",
  author = "Karsten Schmidt",
  note = "https://thi.ng/ecs",
  year = 2019
}

License

© 2019 - 2025 Karsten Schmidt // Apache License 2.0