docs: function createMap(divId) {
    const source = new OSM();
    const layer = new TileLayer({
      source: source
    });
    const map = new Map({
      layers: [layer],
      target: divId,
      view: new View({
        center: [0, 0],
        zoom: 2
      })
    });
    const zoomslider = new ZoomSlider();
    map.addControl(zoomslider);
    return map;
  }