Edit

Layer Swipe

Example of a Layer swipe map.

Example of a Layer swipe map.

Copy 
index.html<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Layer Swipe</title>
    <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <input id="swipe" type="range" style="width: 100%">
    <script src="index.js"></script>
  </body>
</html>
Copy 
index.jsimport 'ol/ol.css';
import Map from 'ol/Map';
import View from 'ol/View';
import TileLayer from 'ol/layer/Tile';
import BingMaps from 'ol/source/BingMaps';
import OSM from 'ol/source/OSM';

var osm = new TileLayer({
  source: new OSM()
});
var bing = new TileLayer({
  source: new BingMaps({
    key: 'Your Bing Maps Key from http://www.bingmapsportal.com/ here',
    imagerySet: 'Aerial'
  })
});

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

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

bing.on('prerender', function(event) {
  var ctx = event.context;
  var width = ctx.canvas.width * (swipe.value / 100);

  ctx.save();
  ctx.beginPath();
  ctx.rect(width, 0, ctx.canvas.width - width, ctx.canvas.height);
  ctx.clip();
});

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

swipe.addEventListener('input', function() {
  map.render();
}, false);
Copy 
package.json{
  "name": "layer-swipe",
  "dependencies": {
    "ol": "6.1.1"
  },
  "devDependencies": {
    "parcel": "1.11.0"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --experimental-scope-hoisting --public-url . index.html"
  }
}