This example uses OpenLayers v10.9.0. The latest is v.
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#### Layer Swipe

swipe 2 openstreetmap 22 maptiler 26

#####

Example of a Layer swipe map.

Example of a Layer swipe map.

##### main.js

    import Map from 'ol/Map.js';
    import View from 'ol/View.js';
    import TileLayer from 'ol/layer/Tile.js';
    import {getRenderPixel} from 'ol/render.js';
    import ImageTile from 'ol/source/ImageTile.js';
    import OSM from 'ol/source/OSM.js';

    const osm = new TileLayer({
      source: new OSM(),
    });

    const key = 'Get your own API key at https://www.maptiler.com/cloud/';
    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 aerial = new TileLayer({
      source: new ImageTile({
        attributions: attributions,
        url: 'https://api.maptiler.com/maps/satellite/{z}/{x}/{y}.jpg?key=' + key,
        tileSize: 512,
        maxZoom: 20,
      }),
    });

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

    const swipe = document.getElementById('swipe');

    aerial.on('prerender', function (event) {
      const ctx = event.context;
      const mapSize = map.getSize();
      const width = mapSize[0] * (Number(swipe.value) / 100);
      const tl = getRenderPixel(event, [width, 0]);
      const tr = getRenderPixel(event, [mapSize[0], 0]);
      const bl = getRenderPixel(event, [width, mapSize[1]]);
      const br = getRenderPixel(event, mapSize);

      ctx.save();
      ctx.beginPath();
      ctx.moveTo(tl[0], tl[1]);
      ctx.lineTo(bl[0], bl[1]);
      ctx.lineTo(br[0], br[1]);
      ctx.lineTo(tr[0], tr[1]);
      ctx.closePath();
      ctx.clip();
    });

    aerial.on('postrender', function (event) {
      const ctx = event.context;
      ctx.restore();
    });

    swipe.addEventListener('input', function () {
      map.render();
    });

##### index.html

    <!DOCTYPE html>
    <html lang="en">
      <head>
        <meta charset="UTF-8">
        <title>Layer Swipe</title>
        <link rel="stylesheet" href="node_modules/ol/ol.css">
        <style>
          .map {
            width: 100%;
            height: 400px;
          }
        </style>
      </head>
      <body>
        <div id="map" class="map"></div>
        <input id="swipe" type="range" style="width: 100%">

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

##### package.json

    {
      "name": "layer-swipe",
      "dependencies": {
        "ol": "10.9.0"
      },
      "devDependencies": {
        "vite": "^3.2.3"
      },
      "scripts": {
        "start": "vite",
        "build": "vite build"
      }
    }