var trackWidget = new Track({
  view: view
});

view.ui.add(trackWidget, "top-left");

Property Overview

Property Details

containerString|HTMLElement inherited

The ID or node representing the DOM element containing the widget. This property can only be set once.

declaredClassStringreadonly inherited

Since: ArcGIS API for JavaScript 4.7

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

destroyedBoolean inherited

When true, this property indicates whether the widget has been destroyed.

geolocationOptionsObject

The HTML5 Geolocation Position options for locating. Refer to Geolocation API Specification for details.

Default Value:{ maximumAge: 0, timeout: 15000, enableHighAccuracy: true }

goToLocationEnabledBoolean

Indicates whether the widget will automatically navigate the view to the user's position when a geolocation result is found. Set to false to disable this behavior, leaving full control to the developer.

Default Value:true

goToOverrideGoToOverride

Since: ArcGIS API 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);
};

graphicGraphicautocast

The graphic used to show the user's location in the view.

Example:

var trackWidget = new Track({
  view: view,  // Assigns the track widget to a view
    graphic: new Graphic({
      symbol: { type: "simple-marker" }  // Overwrites the default symbol used for the
      // graphic placed at the location of the user when found
    })
});

iconClassStringreadonly

Since: ArcGIS API for JavaScript 4.7

The widget's default CSS icon class.

idString inherited

The unique ID assigned to the widget when the widget is created. If not set by the developer, it will default to the container ID, or if that is not present then it will be automatically generated.

labelStringreadonly

Since: ArcGIS API for JavaScript 4.7

The widget's default label.

scaleNumber

Since: ArcGIS API for JavaScript 4.7

Indicates the scale to set on the view when navigating to the position of the geolocated result once a location is returned from the track event. If a scale value is not explicitly set, then the view will navigate to a default scale of 2500. For 2D views the value should be within the effectiveMinScale and effectiveMaxScale.

Default Value:null

Example:

mapView.watch("scale", function (currentScale){
  console.log("scale: %s", currentScale);
});

mapView.when(function(){
  // Create an instance of the Track widget
  var track = new Track({
    view: mapView,
    scale: 5000
  });

  // and add it to the view's UI
  mapView.ui.add(track, "top-left");

  track.start();

  track.on("track", function(trackEvent){
    console.log(trackEvent);
    console.log("track: %s", mapView.scale);
  })
});

trackingBooleanreadonly

Indicates whether the widget is watching for new positions.

Default Value:false

useHeadingEnabledBoolean

Since: ArcGIS API for JavaScript 4.6

Indicates whether the widget will automatically rotate to user's direction. Set to false to disable this behavior.

Default Value:true

viewMapView|SceneView

A reference to the MapView or SceneView. Set this to link the widget to a specific view.

viewModelTrackViewModelautocast

The view model for this widget. This is a class that contains all the logic (properties and methods) that controls this widget's behavior. See the TrackViewModel class to access all properties and methods on the widget.

Method Overview

Method Details

classes(classNames){String}inherited

Since: ArcGIS API for JavaScript 4.7

A utility method used for building the value for a widget's class property. This aids in simplifying CSS class setup.

Prior to version 4.7, there were various approaches towards setting CSS classes. These were dependant upon variables, such as whether the classes were:

• a single static class,
• multiple static classes, or
• dynamic classes.

This helper method takes all of these approaches into account and simplifies it to use one single pattern to accommodate these multiple approaches.

Parameter:

classNames Array<(String|String[]|Object)> repeatable The class names.

Returns:

Type	Description
String	The computed class name.

See also:

• Guide - Widget development (rendering)

Example:

// .tsx syntax showing how to set CSS classes while rendering the widget
render() {
  const dynamicIconClasses = {
    [CSS.myIcon]: this.showIcon,
    [CSS.greyIcon]: !this.showIcon
  };

  return (
    <div class={classes(CSS.root, CSS.mixin, dynamicIconClasses)} />
  );
}

destroy()inherited

Destroys the widget instance.

emit(type, event)inherited

Since: ArcGIS API 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 The event payload.

hasEventListener(type){Boolean}inherited

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.

on(type, listener){Object}inherited

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

Parameters:

type String The name of event to listen for.

listener Function The function to call when the event is fired.

Returns:

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

See also:

• dojo/on

Example:

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

own(handles)inherited

Widget teardown helper. Any handles added to it will be automatically removed when the widget is destroyed.

Parameter:

handles WatchHandle|WatchHandle[] Handles marked for removal once the widget is destroyed.

postInitialize()inherited

This method is primarily used by developers when implementing custom widgets. Executes after widget is ready for rendering.

render(){Object}inherited

This method is primarily used by developers when implementing custom widgets. It must be implemented by subclasses for rendering.

Returns:

Type	Description
Object	The rendered virtual node.

renderNow()inherited

Renders widget to the DOM immediately.

scheduleRender()inherited

This method is primarily used by developers when implementing custom widgets. Schedules widget rendering. This method is useful for changes affecting the UI.

start()

When executed, the widget will start tracking the user's location.

startup()inherited

Deprecated

• since version 4.2.

Deprecated. Finalizes the creation of the widget.

stop()

Stops tracking the user's location when executed.

Event Overview

{position: Object}

{error: Error}

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.