title: Adding a polygon on Mapbox map in Angular 9
body: <p>I'm using <code>mapbox-gl</code> to add a Mapbox map to my Angular app, that works so far. The approach is very similar to this one <a href="https://codepen.io/cansadadeserfeliz/pen/JKmRbQ" rel="nofollow noreferrer">here</a> but I'm unable to find <code>Polygon</code> in the Angular port of that library.</p>
  
  <p>Here's my component code:</p>
  
  <pre><code>private mapElement: ElementRef;
  @ViewChild('map', { static: false }) set content(content: ElementRef) {
      if (content) { // initially setter gets called with undefined
          Object.getOwnPropertyDescriptor(mapboxgl, "accessToken").set(this.mapBoxKey);
          this.map = new mapboxgl.Map({
              container: content.nativeElement,
              style: this.globals.MapboxStyle,
              zoom: 12,
              center: [this.centerLng, this.centerLat]
          });
  
          // Add map controls
          this.map.addControl(new mapboxgl.NavigationControl());
  
          //at this point I'd like to add a polygon....
  
      }
  }
  </code></pre>
  
  <p><code>map.addLayer</code> seems to accept a first argument of type <code>Layer</code> but I'm not sure where to find this type and I'm not able to create an instance of it.</p>
  
  <p>Am I missing a package here ?</p>