text: function loadMap() {
    const map = new mapboxgl.Map({
      container: 'map',
      style: carto.basemaps.darkmatter,
      center: [0, 30],
      zoom: 2,
      scrollZoom: true,
      dragRotate: false,
      touchZoomRotate: false
    });
  
    carto.setDefaultAuth({
      username: 'roman-carto',
      apiKey: 'default_public'
    });
    
    const s = carto.expressions;
    
    const source = new carto.source.Dataset('ne_10m_airports');
    const viz = new carto.Viz(`
      @locationHist: viewportHistogram($location)
      @longitudeHist: viewportHistogram($longitude)
      strokeWidth: 0
    `);
    
    const vizLayer = new carto.Layer('layer', source, viz);
    
    vizLayer.addTo(map); 
    
    return vizLayer;
  }
  