How to destroy mapbox gl map instance

I am using "mapbox-gl": "^0.54.0". While initializing Mapboxgl instance no of web worker thread got created. please see the below image .

here is the sample code. gis-map.component.html

<div #container id="GisMapContainer">

</div>

gis-map.component.ts

import * as MapboxGl from 'mapbox-gl';

@Component({
  selector: 'gis-map',
  templateUrl: './gis-map.component.html',
  styleUrls: ['./gis-map.component.scss']
})
export class MapComponent implements OnInit, OnDestroy {

@ViewChild('container', {static: true}) mapContainer: ElementRef;

ngOnInit(){
let options={
container: this.mapContainer.nativeElement,
...
...
};
this.mapInstance = new MapboxGl.Map(options);
}

ngOnDestroy(){
this.mapInstance=null;
}

}

Now if i am destroying mapbox gl map instance on component destroy but these worker thread instance still exists.

Please give me suggestion it is possible to destroy Javascript vm web worker thread instance.

Thanks.