TrackViewModel

let trackWidget = new Track({
  viewModel: {    // autocasts as new TrackViewModel()
    view: view,   // attaches the Track to the view
  }
};

Property Overview

Property Details

declaredClass Stringreadonly inherited

Since: ArcGIS Maps SDK for JavaScript 4.7

The name of the class. The declared class name is formatted as esri.folder.className.

geolocationOptions Object

An object used for setting optional position parameters. Refer to the Geolocation API Specification for details on using these paramters.

Default Value:null

Example

const track = new Track({
  view: view,
  // Set optional position paramters
  geolocationOptions: {
    maximumAge: 0,
    timeout: 15000,
    enableHighAccuracy: true
  }
});

goToLocationEnabled Boolean

Indicates whether to navigate the view to the position and scale of the geolocated result.

Default Value:true

goToOverride GoToOverride

Since: ArcGIS Maps SDK for JavaScript 4.8

This function provides the ability to override either the MapView goTo() or SceneView goTo() methods.

See also

• MapView
• SceneView

Example

// The following snippet uses the Search widget but can be applied to any
// widgets that support the goToOverride property.
search.goToOverride = function(view, goToParams) {
  goToParams.options.duration = updatedDuration;
  return view.goTo(goToParams.target, goToParams.options);
};

graphic Graphic

The graphic used to show the user's location on the map.

Example

const trackWidget = new Track({
  // Assign the track widget to a view
  view: view,
  // Overwrite the default symbol used for the
  // graphic placed at the location of the user
  graphic: new Graphic ({
   symbol: {
     // autocasts as new SimpleMarkerSymbol()
     type: "simple-marker",
     size: "12px",
     color: "blue",
     // autocasts as new SimpleLineSymbol()
     outline: {
       color: "#efefef",
       width: "1.5px"
     }
   }
 })
});

positionFilterFunction Function

Since: ArcGIS Maps SDK for JavaScript 4.27

A function that is used as an expression to evaluate geolocation points, and returns a boolean value. If the function returns true, the widget will draw a graphic and navigate to the position. The widget will ignore false values and not draw a graphic and not navigate to the position.

Example use cases include smoothing out geolocation anomalies and geofencing.

Default Value:null

Example

// Exclude locations that full outside an extent.
track.viewModel.positionFilterFunction = (value) => {
  const { longitude, latitude } = value.position.coords;
  const myLocation = new Point({ longitude, latitude });
  const geofenceExtent = new Extent({
    // whatever
  });
  return geometryEngine.within(myLocation, geofenceExtent);
};

scale Number

Since: ArcGIS Maps SDK for JavaScript 4.7

Indicates the scale to set on the view when navigating to the position of the geolocated result, after a location is returned from the track event.

By default, the view will navigate to a scale of 2500 for 3D and 4514 for 2D. To override the default in 2D, set the scale property and also set snapToZoom to false. For 2D views the value should be within the effectiveMinScale and effectiveMaxScale.

Default Value:null

state Stringreadonly

The current state of the widget.

Possible Values:"disabled"|"ready"|"tracking"|"waiting"

Default Value:disabled

tracking Booleanreadonly

Indicates whether new positions are being watched.

Default Value:false

view MapView|SceneView

The view associated with the widget.

Method Overview

Method Details

addHandles(handleOrHandles, groupKey)inherited

Since: ArcGIS Maps SDK for JavaScript 4.25

Adds one or more handles which are to be tied to the lifecycle of the object. The handles will be removed when the object is destroyed.

// Manually manage handles
const handle = reactiveUtils.when(
  () => !view.updating,
  () => {
    wkidSelect.disabled = false;
  },
  { once: true }
);

this.addHandles(handle);

// Destroy the object
this.destroy();

Parameters

handleOrHandles WatchHandle|WatchHandle[] Handles marked for removal once the object is destroyed.

groupKey * optional Key identifying the group to which the handles should be added. All the handles in the group can later be removed with Accessor.removeHandles(). If no key is provided the handles are added to a default group.

emit(type, event){Boolean}

Since: ArcGIS Maps SDK for JavaScript 4.5

Emits an event on the instance. This method should only be used when creating subclasses of this class.

Parameters

type String The name of the event.

event Object optional The event payload.

Returns

Type	Description
Boolean	true if a listener was notified

hasEventListener(type){Boolean}

Indicates whether there is an event listener on the instance that matches the provided event name.

Parameter

type String The name of the event.

Returns

Type	Description
Boolean	Returns true if the class supports the input event.

hasHandles(groupKey){Boolean}inherited

Since: ArcGIS Maps SDK for JavaScript 4.25

Returns true if a named group of handles exist.

Parameter

groupKey * optional A group key.

Returns

Type	Description
Boolean	Returns true if a named group of handles exist.

Example

// Remove a named group of handles if they exist.
if (obj.hasHandles("watch-view-updates")) {
  obj.removeHandles("watch-view-updates");
}

on(type, listener){Object}

Registers an event handler on the instance. Call this method to hook an event with a listener.

Parameters

type String|String[] An event or an array of events to listen for.

listener Function The function to call when the event fires.

Returns

Type	Description
Object	Returns an event handler with a remove() method that should be called to stop listening for the event(s). Property Type Description remove Function When called, removes the listener from the event.

Example

view.on("click", function(event){
  // event is the event handle returned after the event fires.
  console.log(event.mapPoint);
});

removeHandles(groupKey)inherited

Since: ArcGIS Maps SDK for JavaScript 4.25

Removes a group of handles owned by the object.

Parameter

groupKey * optional A group key or an array or collection of group keys to remove.

Example

obj.removeHandles(); // removes handles from default group

obj.removeHandles("handle-group");
obj.removeHandles("other-handle-group");

start()

When executed, tracking starts at the user's location.

stop()

Stops tracking the user's location when executed.

Event Overview

Event Details

track

Fires after the start() method is called and a position is found.

Property

position Object Geoposition returned from the Geolocation API.

track-error

Fires after the start() method is called and an error is returned.

Property

error Error The Error object returned if an error occurred while tracking.