KAPLAY

KAPLAY is a JavaScript library that helps you make games fast and fun!

Start playing around with it in the KAPLAYGROUND

Examples

// initialize context
kaplay();

// define gravity
setGravity(2400);

// load a sprite called "bean"
loadSprite("bean", "sprites/bean.png");

// compose the player game object from multiple components and add it to the game
const bean = add([
    sprite("bean"),
    pos(80, 40),
    area(),
    body(),
]);

// press space to jump
onKeyPress("space", () => {
    // this method is provided by the "body" component above
    bean.jump();
});

KAPLAY uses a powerful component system to compose game objects and behaviors.

// add a game obj to the scene from a list of component
const player = add([
    // it renders as a sprite
    sprite("bean"),
    // it has a position
    pos(100, 200),
    // it has a collider
    area(),
    // it is a physical body which will respond to physics
    body(),
    // it has 8 of health
    health(8),
    // or give it tags for easier group behaviors
    "player",
    "friendly",
    // plain objects fields are directly assigned to the game obj
    {
        dir: vec2(-1, 0),
        dead: false,
        speed: 240,
    },
]);

Blocky imperative syntax for describing behaviors

// .onCollide() comes from "area" component
player.onCollide("enemy", () => {
    // .hurt() comes from "health" component
    player.hurt(1);
});

// check fall death
player.onUpdate(() => {
    if (player.pos.y >= height()) {
        destroy(player);
        gameOver();
    }
});

// if 'player' onCollide with any object with tag "enemy", run the callback
player.onCollide("enemy", () => {
    player.hp -= 1;
});

// all objects with tag "enemy" will move towards 'player' every frame
onUpdate("enemy", (e) => {
    e.move(player.pos.sub(e.pos).unit().scale(e.speed));
});

// move up 100 pixels per second every frame when "w" key is held down
onKeyDown("w", () => {
    player.move(0, 100);
});

Usage

Start a Project With create-kaplay

The fastest way to start a KAPLAY game is with create-kaplay

$ npx create-kaplay mygame

This will create a directory called mygame for you, containing all the files we need

$ cd mygame
$ npm run dev

Then open http://localhost:5173 and edit src/game.js

Install as NPM Package

$ npm install kaplay

import kaplay from "kaplay";

kaplay();

add([
    text("oh hi"),
    pos(80, 40),
]);

also works with CommonJS

const kaboom = require("kaplay");

Note that you'll need to use a bundler like esbuild or webpack to use KAPLAY with NPM

Browser CDN

This exports a global kaplay function

<script src="https://unpkg.com/kaplay@3000.1.17/dist/kaboom.js"></script>
<script>
kaplay()
</script>

or use with es modules

<script type="module">
import kaplay from "https://unpkg.com/kaplay@3000.1.17/dist/kaboom.mjs"
kaplay()
</script>

works all CDNs that supports NPM packages, e.g. jsdelivr, skypack

Documentation

• v3001: https://kaplayjs.com/
• v3000: https://kaboomjs.com/
• v2000: https://2000.kaboomjs.com/
• v0.5.0: https://legacy.kaboomjs.com/

Community

• Discord Server
• GitHub Discussions
• Twitter

Games

Collections of games made with KAPLAY (and Kaboom), selected by KAPLAY:

• Itch.io
• Newgrounds.com

Credits

• Thanks to tga for all his work on the original Kaboom.js
• Thanks to mulfok for the awesome mulfok32 color palette, used in KAPLAY sprites and art
• Thanks to Pixabay for the great burp sound, used in burp() function
• Thansk to Kenney for all used assets for examples
  • Impact Sound Pack
  • 1-Bit Platformer Pack
• Thanks to abrudz for the amazing APL386 font
• Thanks to Polyducks for the amazing kitchen sink font font
• Thanks to 0x72 for the amazing Dungeon Tileset