js13k-ecs

A 1kb entity component system, designed for js13k.

• Tiny: weighs about one kilobyte gzipped

Install

This project uses node and npm. Go check them out if you don't have them locally installed.

$ npm install js13k-ecs

Then with a module bundler like rollup or webpack, use as you would anything else:

// using ES6 modules
import ecs from 'js13k-ecs';
 
// using CommonJS modules
var ecs = require('js13k-ecs');

The UMD build is also available on unpkg:

<script src="https://unpkg.com/js13k-ecs/dist/ecs.umd.js"></script>

You can find the library on window.ecs.

Usage

See example folder. Live example

API

ecs

register(...Components)

Registers components for use by the library. Components must be classes or constructor functions. No other requirements are imposed on the components.

process(...systems)

Adds systems for use by the library. Systems must be instances of classes or objects. Systems must implement the update method.

create(id)

Creates the entity with the specified id. If id is not specified, serial numbers starting with 1 are generated and encoded in base36. Returns the created entity.

get(id)

Returns the entity with the specified id or undefined if it is not present.

select(...Components)

Returns a selection of entities that have the specified set of components. The sample is updated real-time and always relevant.

The selector has the length property, which stores the number of entities in the sample and the iterate(fn) method, with which you can loop through all entities.

update(delta)

Successively calls update methods on all systems, passing them the delta parameter. Returns the object that contains the duration of the execution of the systems.

Entity

add(...components)

Adds the components to the entity.

remove(...Components)

Removes components of the Components class from the entity. Calls the destructor method of each component if it is present.

has(Component)

Returns true if the entity has a component of the Component class and false otherwise.

get(Component)

Returns a component of the Component class or undefined if it is not present.

eject()

Removes the entity from all selectors and sets its id to zero. Calls the destructor method of each component if it is present.