Loading Spinner

Example using load events to show a loading spinner.

You can listen for the map's loadstart and loadend events to show a loading spinner on top of the map.

main.js

import ImageTile from 'ol/source/ImageTile.js';
import Map from 'ol/Map.js';
import TileLayer from 'ol/layer/Tile.js';
import View from 'ol/View.js';

const key = 'get_your_own_D6rA4zTHduk6KOKTXzGB';
const attributions =
  '<a href="https://www.maptiler.com/copyright/" target="_blank">&copy; MapTiler</a> ' +
  '<a href="https://www.openstreetmap.org/copyright" target="_blank">&copy; OpenStreetMap contributors</a>';

const source = new ImageTile({
  attributions: attributions,
  url: 'https://api.maptiler.com/maps/streets-v2/{z}/{x}/{y}.png?key=' + key,
  tileSize: 512,
});

const map = new Map({
  layers: [new TileLayer({source: source})],
  target: 'map',
  view: new View({
    center: [0, 0],
    zoom: 2,
  }),
});

map.on('loadstart', function () {
  map.getTargetElement().classList.add('spinner');
});
map.on('loadend', function () {
  map.getTargetElement().classList.remove('spinner');
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Loading Spinner</title>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <style>
      .map {
        width: 100%;
        height: 400px;
      }
      .map {
        background: #85ccf9;
        position: relative;
      }
      #map {
        height: 400px;
        position: relative;
      }

      @keyframes spinner {
        to {
          transform: rotate(360deg);
        }
      }

      .spinner:after {
        content: "";
        box-sizing: border-box;
        position: absolute;
        top: 50%;
        left: 50%;
        width: 40px;
        height: 40px;
        margin-top: -20px;
        margin-left: -20px;
        border-radius: 50%;
        border: 5px solid rgba(180, 180, 180, 0.6);
        border-top-color: rgba(0, 0, 0, 0.6);
        animation: spinner 0.6s linear infinite;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>

    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "load-events",
  "dependencies": {
    "ol": "10.2.1"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}