ujs/src/js/game.js

import { App } from './app.js';
import { Scene, SceneLayer } from './scene.js';
import { Rect, StrokeRect } from './objects.js';

let app = new App(document.querySelector('canvas'), 400, 400);

let firstScene = new Scene(app.canvas, app.context, 400, 400);
let firstLayer = new SceneLayer('background', [
  new Rect(50, 50, 100, 100, 'red'),
  new StrokeRect(150, 150, 40, 40, 'green', 'blue', 1),
]);
firstScene.addLayer(firstLayer);

app.scene = firstScene;

// add app view in document
window.addEventListener('DOMContentLoaded', () => {
  document.body.appendChild(app.view);
});