Getting Geolocation on Mobile Devices using Vue.js + TypeScript + ASP.NET Core

hello.ts

...
export default class Hello extends Vue {
  ...

  latitude?: number = null;
  longitude?: number = null;
  altitude?: number = null;

  ...

  public getLocation (): void {
    var geo: Geolocation = navigator.geolocation;
    if (geo == null) {
      console.log("No geolocation support");
      return;
    }

    var options: PositionOptions = new GpsPositionOptions(true, 30000, 30000);
    geo.getCurrentPosition((p: Position) => this.success(p), (ex: PositionError) => this.error(ex), options);
  }

  private success (position: Position): PositionCallback {
    this.latitude = position.coords.latitude;
    this.longitude = position.coords.longitude;
    this.altitude = position.coords.altitude;

    return null;
  }

  private error(ex: PositionError): PositionErrorCallback {
    console.log(ex.message);
    return null;
  }
}