Help to test if Giro3D correctly deallocates memory.

100% Map style by Stamen Design, © OpenStreetMap contributors
index.js 
import StadiaMaps from "ol/source/StadiaMaps.js";

import { MapControls } from "three/examples/jsm/controls/MapControls.js";

import Extent from "@giro3d/giro3d/core/geographic/Extent.js";
import Instance from "@giro3d/giro3d/core/Instance.js";
import ColorLayer from "@giro3d/giro3d/core/layer/ColorLayer.js";
import Map from "@giro3d/giro3d/entities/Map.js";
import Inspector from "@giro3d/giro3d/gui/Inspector.js";
import TiledImageSource from "@giro3d/giro3d/sources/TiledImageSource.js";

function bindToggle(id, onChange) {
  const element = document.getElementById(id);
  if (!(element instanceof HTMLInputElement)) {
    throw new Error(
      "invalid binding element: expected HTMLButtonElement, got: " +
        element.constructor.name,
    );
  }

  element.oninput = function oninput() {
    onChange(element.checked);
  };

  const callback = (v) => {
    element.checked = v;
    onChange(element.checked);
  };

  return [callback, element.checked, element];
}

const extent = new Extent(
  "EPSG:3857",
  -20037508.342789244,
  20037508.342789244,
  -20037508.342789244,
  20037508.342789244,
);
const dimensions = extent.dimensions();

let instance = null;
let inspector = null;
let controls = null;

let map = null;

function init() {
  instance = new Instance({
    target: "view",
    crs: extent.crs,
    backgroundColor: 0x0a3b59,
  });

  map = new Map({ extent });

  instance.add(map);

  // Adds an TMS imagery layer
  map
    .addLayer(
      new ColorLayer({
        name: "osm",
        source: new TiledImageSource({
          source: new StadiaMaps({ layer: "stamen_watercolor", wrapX: false }),
        }),
      }),
    )
    .catch((e) => console.error(e));

  instance.view.camera.position.set(
    (Math.random() - 0.5) * dimensions.x,
    (Math.random() - 0.5) * dimensions.y,
    25000000,
  );

  controls = new MapControls(instance.view.camera, instance.domElement);

  instance.view.setControls(controls);

  inspector = Inspector.attach("inspector", instance);
}

init();

function reload() {
  if (!instance) {
    return;
  }

  map.getLayers().forEach((l) => l.dispose());
  inspector.detach();
  instance.dispose();
  controls.dispose();
  inspector = null;
  instance = null;
  controls = null;
  init();
}

document.getElementById("load_once").addEventListener("click", reload);

let intervalId;

bindToggle("autoreload", (state) => {
  clearInterval(intervalId);

  if (state) {
    intervalId = setInterval(reload, 2000);
  }
});
index.html 
<!doctype html>
<html lang="en">
  <head>
    <title>Dispose instance</title>
    <meta charset="UTF-8" />
    <meta name="name" content="instance_disposing" />
    <meta
      name="description"
      content="Help to test if Giro3D correctly deallocates memory."
    />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />

    <link rel="icon" href="https://giro3d.org/images/favicon.svg" />
    <link
      href="https://giro3d.org/assets/bootstrap-custom.css"
      rel="stylesheet"
    />
    <script src="https://giro3d.org/assets/bootstrap.bundle.min.js"></script>
    <link
      rel="stylesheet"
      type="text/css"
      href="https://giro3d.org/latest/css/example.css"
    />
  </head>

  <body>
    <div id="view" class="m-0 p-0 w-100 h-100"></div>
    <div
      id="inspector"
      class="position-absolute top-0 start-0 mh-100 overflow-auto"
    ></div>

    <div class="side-pane-with-status-bar">
      <div class="card" id="buttons-container">
        <div class="card-body">
          <div class="form-check form-switch mb-3">
            <input
              class="form-check-input"
              type="checkbox"
              role="switch"
              id="autoreload"
              autocomplete="off"
            />
            <label class="form-check-label" for="autoreload"
              >Reload Giro3D every 2 seconds</label
            >
          </div>

          <button id="load_once" class="btn btn-primary">
            Dispose and reload Giro3D once
          </button>
        </div>
      </div>
    </div>

    <script type="module" src="index.js"></script>
    <script>
      /* activate popovers */
      const popoverTriggerList = [].slice.call(
        document.querySelectorAll('[data-bs-toggle="popover"]'),
      );
      popoverTriggerList.map(
        // bootstrap is used as script in the template, disable warning about undef
        // eslint-disable-next-line no-undef
        (popoverTriggerEl) =>
          new bootstrap.Popover(popoverTriggerEl, {
            trigger: "hover",
            placement: "left",
            content: document.getElementById(
              popoverTriggerEl.getAttribute("data-bs-content"),
            ).innerHTML,
            html: true,
          }),
      );
    </script>
  </body>
</html>
package.json 
{
    "name": "instance_disposing",
    "dependencies": {
        "@giro3d/giro3d": "0.39.0"
    },
    "devDependencies": {
        "vite": "^3.2.3"
    },
    "scripts": {
        "start": "vite",
        "build": "vite build"
    }
}