Track | API Reference | ArcGIS Maps SDK for JavaScript

Provides a simple button that animates the View to the user's location when clicked. The view rotates based on device heading. While tracking, the default button looks like the following:

track-button

The default heading symbol will display when speed is greater than zero and the browser provides heading information:

heading-indicator

You can use the view's DefaultUI to add widgets to the view's user interface via the ui property.

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

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

The Track widget is only available in secure contexts, such as HTTPS. Note that localhost is considered "potentially secure" and can be used for easy testing in browsers that support Window.isSecureContext.

For additional information regarding this, visit the ArcGIS blog, Increased Web API security in Google Chrome.

Known Limitations

The heading symbol is not currently supported in 3D SceneViews.
The Track widget does not work concurrently with the Locate widget. Only one of the widgets can be used at a time.

See also

Constructors

Track Constructor new Track(properties)

Parameter

properties Object

optional

See the properties for a list of all the properties that may be passed into the constructor.

Example

// typical usage
let track = new Track({
  view: view
});

Property Overview

Any properties can be set, retrieved or listened to. See the Watch for changes topic.

Show inherited properties

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Type	Summary	Class
HTMLElement\|null\|undefined	The ID or node representing the DOM element containing the widget.	Widget
String	The name of the class.	Accessor
Boolean	When `true`, this property indicates whether the widget has been destroyed.	Widget
Object\|null\|undefined	An object used for setting optional position parameters.	Track
Boolean	Indicates whether the widget will automatically navigate the view to the user's position when a geolocation result is found.	Track
GoToOverride\|null\|undefined	This function provides the ability to override either the MapView goTo() or SceneView goTo() methods.	Track
Graphic	The graphic used to show the user's location on the map.	Track
String	Icon displayed in the widget's button.	Track
String	The unique ID assigned to the widget when the widget is created.	Widget
String	The widget's default label.	Track
Boolean	Indicates whether the widget will automatically rotate to the device heading based on the Geolocation APIs `GeolocationCoordinates.heading` property.	Track
Number\|null\|undefined	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.	Track
Boolean	Indicates whether the widget is watching for new positions.	Track
MapView\|SceneView\|null\|undefined	A reference to the MapView or SceneView.	Track
TrackViewModel	The viewModel for this widget.	Track
Boolean	Indicates whether the widget is visible.	Widget

Property Details

container Inherited Property container HTMLElement |null |undefinedautocast Inherited from Widget Autocasts from String

The ID or node representing the DOM element containing the widget. This property can only be set once. The following examples are all valid use case when working with widgets.

Examples

// Create the HTML div element programmatically at runtime and set to the widget's container
const basemapGallery = new BasemapGallery({
  view: view,
  container: document.createElement("div")
});

// Add the widget to the top-right corner of the view
view.ui.add(basemapGallery, {
  position: "top-right"
});

// Specify an already-defined HTML div element in the widget's container

const basemapGallery = new BasemapGallery({
  view: view,
  container: basemapGalleryDiv
});

// Add the widget to the top-right corner of the view
view.ui.add(basemapGallery, {
  position: "top-right"
});

// HTML markup
<body>
  <div id="viewDiv"></div>
  <div id="basemapGalleryDiv"></div>
</body>

// Specify the widget while adding to the view's UI
const basemapGallery = new BasemapGallery({
  view: view
});

// Add the widget to the top-right corner of the view
view.ui.add(basemapGallery, {
  position: "top-right"
});

declaredClass Inherited Property declaredClass Stringreadonly Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.7 Accessor since 4.0, declaredClass added at 4.7.

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

destroyed Inherited Property destroyed Boolean Inherited from Widget

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

geolocationOptions Property geolocationOptions Object |null |undefined

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

Default Value:null

Example

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

goToLocationEnabled Property goToLocationEnabled Boolean

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

goToOverride Property goToOverride GoToOverride |null |undefined Since: ArcGIS Maps SDK for JavaScript 4.8 Track since 4.0, goToOverride added at 4.8.

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

See also

Example

// The following snippet uses Search 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 Property graphic Graphicautocast

The graphic used to show the user's location on the map. Overriding this will disable the default graphic's heading indicator.

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"
     }
   }
 })
});

icon Property icon String Since: ArcGIS Maps SDK for JavaScript 4.28 Track since 4.0, icon added at 4.28.

Icon displayed in the widget's button.

Default Value:"compass-north-circle"

See also

Calcite Icon Search

id Inherited Property id String Inherited from Widget

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.

label Property label String Since: ArcGIS Maps SDK for JavaScript 4.7 Track since 4.0, label added at 4.7.

The widget's default label.

rotationEnabled Property rotationEnabled Boolean Since: ArcGIS Maps SDK for JavaScript 4.27 Track since 4.0, rotationEnabled added at 4.27.

Indicates whether the widget will automatically rotate to the device heading based on the Geolocation APIs GeolocationCoordinates.heading property. The map will not rotate if the speed is 0, or if the device is unable to provide heading information.

Set to false to disable this behavior.

Default Value:true

scale Property scale Number |null |undefined Since: ArcGIS Maps SDK for JavaScript 4.7 Track since 4.0, scale added at 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

Example

const mapView = new MapView({
  map: map,
  container: "viewDiv",
  // Turn off snapToZoom
  constraints: {
    snapToZoom: false
  }
});

mapView.when(() => {
  // Create an instance of the Track widget
  let track = new Track({
    view: mapView,
    // Set a new default scale
    scale: 5000
  });

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

tracking Property tracking Booleanreadonly

Indicates whether the widget is watching for new positions.

Default Value:false

view Property view MapView |SceneView |null |undefined

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

viewModel Property viewModel TrackViewModelautocast

The viewModel 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.

visible Inherited Property visible Boolean Inherited from Widget

Indicates whether the widget is visible.

If false, the widget will no longer be rendered in the web document. This may affect the layout of other elements or widgets in the document. For example, if this widget is the first of three widgets associated to the upper right hand corner of the view UI, then the other widgets will reposition when this widget is made invisible. For more information, refer to the css display value of "none".

Default Value:true

Example

// Hides the widget in the view
widget.visible = false;

Method Overview

Show inherited methods

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Return Type	Summary	Class
	Adds one or more handles which are to be tied to the lifecycle of the object.	Accessor
String	A utility method used for building the value for a widget's `class` property.	Widget
	Destroys the widget instance.	Widget
Boolean	Emits an event on the instance.	Widget
Boolean	Indicates whether there is an event listener on the instance that matches the provided event name.	Widget
Boolean	Returns true if a named group of handles exist.	Accessor
Boolean	`isFulfilled()` may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected).	Widget
Boolean	`isRejected()` may be used to verify if creating an instance of the class is rejected.	Widget
Boolean	`isResolved()` may be used to verify if creating an instance of the class is resolved.	Widget
Object	Registers an event handler on the instance.	Widget
	Executes after widget is ready for rendering.	Widget
	Removes a group of handles owned by the object.	Accessor
Object	This method is implemented by subclasses for rendering.	Widget
	Renders widget to the DOM immediately.	Widget
	Schedules widget rendering.	Widget
	When executed, the widget will start tracking the user's location.	Track
	Stops tracking the user's location when executed.	Track
Promise	`when()` may be leveraged once an instance of the class is created.	Widget

Method Details

addHandles Inherited Method addHandles(handleOrHandles, groupKey) Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, addHandles added at 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.

classes Inherited Method classes(classNames){String} Inherited from Widget Since: ArcGIS Maps SDK for JavaScript 4.7 Widget since 4.2, classes added at 4.7.

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

Parameter

classNames String|String []|Object

repeatable

The class names.

Returns

Type	Description
String	The computed class name.

Example

// .tsx syntax showing how to set css classes while rendering the widget

render() {
  const dynamicClasses = {
    [css.flip]: this.flip,
    [css.primary]: this.primary
  };

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

destroy Inherited Method destroy() Inherited from Widget

Destroys the widget instance.

emit Inherited Method emit(type, event){Boolean} Inherited from Widget Since: ArcGIS Maps SDK for JavaScript 4.5 Widget since 4.2, emit added at 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 Inherited Method hasEventListener(type){Boolean} Inherited from Widget

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 Inherited Method hasHandles(groupKey){Boolean} Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, hasHandles added at 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");
}

isFulfilled Inherited Method isFulfilled(){Boolean} Inherited from Widget

isFulfilled() may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected). If it is fulfilled, true will be returned.

Returns

Type	Description
Boolean	Indicates whether creating an instance of the class has been fulfilled (either resolved or rejected).

isRejected Inherited Method isRejected(){Boolean} Inherited from Widget

isRejected() may be used to verify if creating an instance of the class is rejected. If it is rejected, true will be returned.

Returns

Type	Description
Boolean	Indicates whether creating an instance of the class has been rejected.

isResolved Inherited Method isResolved(){Boolean} Inherited from Widget

isResolved() may be used to verify if creating an instance of the class is resolved. If it is resolved, true will be returned.

Returns

Type	Description
Boolean	Indicates whether creating an instance of the class has been resolved.

on Inherited Method on(type, listener){Object} Inherited from Widget

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);
});

postInitialize Inherited Method postInitialize() Inherited from Widget

Executes after widget is ready for rendering.

removeHandles Inherited Method removeHandles(groupKey) Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, removeHandles added at 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");

render Inherited Method render(){Object} Inherited from Widget

This method is implemented by subclasses for rendering.

Returns

Type	Description
Object	The rendered virtual node.

renderNow Inherited Method renderNow() Inherited from Widget

Renders widget to the DOM immediately.

scheduleRender Inherited Method scheduleRender() Inherited from Widget

Schedules widget rendering. This method is useful for changes affecting the UI.

start Method start()

When executed, the widget will start tracking the user's location. Only start the widget on a user gesture such as a click event.

stop Method stop()

Stops tracking the user's location when executed.

when Inherited Method when(onFulfilled, onRejected){Promise} Inherited from Widget Since: ArcGIS Maps SDK for JavaScript 4.6 Widget since 4.2, when added at 4.6.

when() may be leveraged once an instance of the class is created. This method takes two input parameters: a onFulfilled function and an onRejected function. The onFulfilled executes when the instance of the class loads. The onRejected executes if the instance of the class fails to load.

Parameters

onFulfilled Function

optional

The function to call when the promise resolves.

onRejected Function

optional

The function to execute when the promise fails.

Returns

Type	Description
Promise	Returns a new promise for the result of `onFulfilled` that may be used to chain additional functions.

Example

// Although this example uses MapView, any class instance that is a promise may use when() in the same way
let view = new MapView();
view.when(function(){
  // This function will execute once the promise is resolved
}, function(error){
  // This function will execute if the promise is rejected due to an error
});

Event Overview

Name	Type	Summary	Class
	{position: Object}	Fires after the start() method is called and a position is found.	Track
	{error: Error}	Fires after the start() method is called and an error is returned.	Track

Event Details

track Event track

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

Property: position Object

Geolocation coordinates returned from the Geolocation API.

Example

track.on("track", ({ position }) => {
  const { longitude, latitude } = position.coords;
  console.log("Track", `${longitude.toFixed(4)}, ${latitude.toFixed(4)}`);
});

track-error Event 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.