Edit

Reusable Source

Updating a tile source by changing the URL.

You can call source.setUrl() to update the URL for a tile source. Note that when you change the URL for a tile source, existing tiles will not be replaced until new tiles are loaded. If you are interested instead in clearing currently rendered tiles, you can call the source.refresh() method. Alternatively, you can use two separate sources if you want to remove rendered tiles and start over loading new tiles.

main.js
import 'ol/ol.css';
import Map from 'ol/Map';
import TileLayer from 'ol/layer/Tile';
import View from 'ol/View';
import XYZ from 'ol/source/XYZ';

const key =
  'Your Mapbox access token from https://mapbox.com/ here';
const baseUrl = 'https://{a-c}.tiles.mapbox.com/v4';
const urls = [
  baseUrl + '/mapbox.blue-marble-topo-jan/{z}/{x}/{y}.png?access_token=' + key,
  baseUrl +
    '/mapbox.blue-marble-topo-bathy-jan/{z}/{x}/{y}.png?access_token=' +
    key,
  baseUrl + '/mapbox.blue-marble-topo-jul/{z}/{x}/{y}.png?access_token=' + key,
  baseUrl +
    '/mapbox.blue-marble-topo-bathy-jul/{z}/{x}/{y}.png?access_token=' +
    key,
];

const source = new XYZ();

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

function updateUrl(index) {
  source.setUrl(urls[index]);
}

const buttons = document.getElementsByClassName('switcher');
for (let i = 0, ii = buttons.length; i < ii; ++i) {
  const button = buttons[i];
  button.addEventListener('click', updateUrl.bind(null, Number(button.value)));
}

updateUrl(0);
index.html
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Reusable Source</title>
    <!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
    <script src="https://unpkg.com/elm-pep"></script>
    <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v3/polyfill.min.js?features=fetch,requestAnimationFrame,Element.prototype.classList,URL,TextDecoder,Number.isInteger"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <button class="switcher" value="0">January</button>
    <button class="switcher" value="1">January (with bathymetry)</button>
    <button class="switcher" value="2">July</button>
    <button class="switcher" value="3">July (with bathymetry)</button>
    <script src="main.js"></script>
  </body>
</html>
package.json
{
  "name": "reusable-source",
  "dependencies": {
    "ol": "6.9.0"
  },
  "devDependencies": {
    "parcel": "^2.0.0-beta.1"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --public-url . index.html"
  }
}