minimojs

MinimoJS v1

Ultra-minimal, deterministic 2D web game engine for browser games.

MinimoJS focuses on a flat API, direct game-loop control, and fast iteration for small games and agent-generated prototypes.

This README is intentionally high-level. It explains what the project is and how to use it quickly, without listing the full API surface.

What MinimoJS Is

• ESM-only TypeScript-first engine
• Single Game entry point
• Emoji-based sprite rendering
• rAF-driven loop (timers/animations/updates)
• Responsive auto-centered canvas

Core Conventions

• Time arguments are milliseconds (ms)
• Rotation uses degrees
• Runtime update delta (dt) is seconds
• Coordinate system is center-based world space
• Positive Y goes downward
• For new mobile-first games, prefer a portrait canvas of 720x1280

What It Intentionally Avoids

• Heavy scene-manager/ECS architecture
• Heavy physics engine features
• Image spritesheets and asset pipelines
• Nested subsystem APIs
• setTimeout / setInterval game loops

Install

npm install minimojs

Quick Start

import { DrawSprite, Game, Sprite, type IScene } from "minimojs";

const game = new Game(720, 1280);
game.gravityY = 980;

class MeterSprite extends DrawSprite {
  public value = 0.5;

  constructor(x: number, y: number) {
    super(160, 28, x, y);
  }

  redraw(ctx: CanvasRenderingContext2D) {
    ctx.fillStyle = "#1a2236";
    ctx.fillRect(0, 0, this.width, this.height);
    ctx.fillStyle = "#7ce7ff";
    ctx.fillRect(0, 0, this.width * this.value, this.height);
  }
}

class DemoScene implements IScene {
  private player: Sprite | null = null;
  private meter: MeterSprite | null = null;

  onCreate() {
    this.player = game.add(new Sprite("🐢", 360, 640, 48));
    this.player.gravityScale = 1;
    this.meter = game.add(new MeterSprite(360, 80));
    this.meter.ignoreScroll = true;
  }

  onUpdate(dt: number) {
    if (!this.player) return;

    if (game.isKeyDown("ArrowLeft")) this.player.vx = -200;
    else if (game.isKeyDown("ArrowRight")) this.player.vx = 200;
    else this.player.vx = 0;

    if (game.isKeyPressed(" ")) this.player.vy = -600;
    if (this.meter) this.meter.value = Math.abs(this.player.vx) / 200;
    game.drawText("MinimoJS", 10, 10, 16);
  }
}

game.start(new DemoScene());

Note: drawText() uses "Press Start 2P", monospace. Load the font in your HTML if you want pixel-font styling.

Examples

• examples/chickens-eggs-basket/
• examples/run-dino-run/
• examples/space-invader/
• examples/super-minimo-bros/
• examples/scale-shift/
• examples/background-desert/
• examples/scene-lab/
• examples/image-sprite-sad-plush/
• examples/draw-sprite/
• examples/pseudo-3d-racer/
• examples/animations/

Run locally from the minimojs directory:

npx serve .

Full API Reference

For complete API details, use source/docs generated from types:

• dist/minimo.d.ts
• src/minimo.ts (JSDoc)

Development

npm run build
npm run clean
npm run rebuild
npm run pack:check

License

MIT