Property Overview

Property Details

declaredClassStringreadonly inherited

Since: ArcGIS API for JavaScript 4.7

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

fullExtentExtentautocast

The full extent of the layer. By default, this is worldwide. This property may be used to set the extent of the view to match a layer's extent so that its features appear to fill the view. See the sample snippet below.

Example:

// Once the layer loads, set the view's extent to the layer's fullextent
layer.when(function(){
  view.extent = layer.fullExtent;
});

idString

The unique ID assigned to the layer. If not set by the developer, it is automatically generated when the layer is loaded.

listModeString

Indicates how the layer should display in the LayerList widget. The possible values are listed below.

Value	Description
show	The layer is visible in the table of contents.
hide	The layer is hidden in the table of contents.
hide-children	If the layer is a GroupLayer, hide the children layers from the table of contents.

Default Value:show

loadedBooleanreadonly

Indicates whether the layer's resources have loaded. When true, all the properties of the object can be accessed.

Default Value:false

loadErrorErrorreadonly

The Error object returned if an error occurred while loading.

Default Value:null

loadStatusStringreadonly

Represents the status of a load operation.

Value	Description
not-loaded	The object's resources have not loaded.
loading	The object's resources are currently loading.
loaded	The object's resources have loaded without errors.
failed	The object's resources failed to load. See loadError for more details.

Default Value:not-loaded

loadWarningsObject[]readonly

A list of warnings which occurred while loading.

opacityNumber

The opacity of the layer. This value can range between 1 and 0, where 0 is 100 percent transparent and 1 is completely opaque.

Default Value:1

Example:

// Makes the layer 50% transparent
layer.opacity = 0.5;

titleString

The title of the layer used to identify it in places such as the Legend and LayerList widgets.

typeStringreadonly

The layer type provides a convenient way to check the type of the layer without the need to import specific layer modules.

Possible values: base-dynamic | base-elevation | base-tile | bing-maps | elevation | feature | graphics | group | imagery | integrated-mesh | map-image | open-street-map | point-cloud | scene | stream | tile | unknown | unsupported | vector-tile | web-tile

visibleBoolean

Indicates if the layer is visible in the View. When false, the layer may still be added to a Map instance that is referenced in a view, but its features will not be visible in the view.

Default Value:true

Example:

// The layer is no longer visible in the view
layer.visible = false;

Method Overview

Method Details

cancelLoad()

Cancels a load() operation if it is already in progress.

emit(type, event)

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.

fetchAttributionData(){Promise<Object>}

Fetches custom attribution data for the layer when it becomes available.

Returns:

Type	Description
Promise<Object>	Resolves to an object containing custom attribution data for the layer.

fromArcGISServerUrl(params){Promise<Layer>}static

Creates a new layer instance from an ArcGIS Server URL. Depending on the URL, the returned layer type may be a FeatureLayer, TileLayer, MapImageLayer, SceneLayer, StreamLayer, ElevationLayer or GroupLayer.

This is useful when you work with various ArcGIS Server URLs, but you don't necessarily know which layer type(s) they create. This method creates the appropriate layer type for you. In case of a feature service or a scene service, when the URL points to the service and the service has multiple layers, the returned promise will resolve to a GroupLayer.

Parameters:

params Object Input parameters for creating the layer. Specification: url String The ArcGIS Server URL used to create the layer. properties Object optional Set any of the layer's properties here for constructing the layer instance (e.g. popupTemplate, renderer, etc.).

Returns:

Type	Description
Promise<Layer>	Returns a promise that resolves to the new Layer instance.

Example:

// get an ArcGIS server url from a custom function
var arcgisUrl = getLayerUrl();

Layer.fromArcGISServerUrl({
  url: arcgisUrl,
  properties: {
    // set any layer properties here
    popupTemplate: new PopupTemplate()
  }
}).then(function(layer){
  // add the layer to the map
  map.add(layer);
});

fromPortalItem(params){Promise<Layer>}static

Creates a new layer instance of the appropriate layer class from an ArcGIS Online or ArcGIS Enterprise portal item. If the item points to a feature service with multiple layers, then a GroupLayer is created. If the item points to a service with a single layer, then it resolves to a layer of the same type of class as the service.

See also: isLayer

Parameters:

params Object The parameters for loading the portal item. Specification: portalItem PortalItem The object representing an ArcGIS Online or ArcGIS Enterprise portal item from which to load the layer.

Returns:

Type	Description
Promise<Layer>	Returns a promise which resolves to the new layer instance.

Example:

Layer.fromPortalItem({
  portalItem: {  // autocasts new PortalItem()
    id: "8444e275037549c1acab02d2626daaee"
  }
}).then(function(layer){
  // add the layer to the map
  map.add(layer);
});

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.

isFulfilled(){Boolean}

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(){Boolean}

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(){Boolean}

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.

load(){Promise}

Loads the resources referenced by this class. This method automatically executes for a View and all of the resources it references in Map if the view is constructed with a map instance.

This method must be called by the developer when accessing a resource that will not be loaded in a View.

Returns:

Type	Description
Promise	Resolves when the resources have loaded.

on(type, listener){Object}

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);
});

when(callback, errback){Promise}

Since: ArcGIS API for JavaScript 4.6

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

Parameters:

callback Function optional The function to call when the promise resolves.

errback Function optional The function to execute when the promise fails.

Returns:

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

Example:

// Although this example uses MapView, any class instance that is a promise may use then() in the same way
var 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

{view: View,layerView: LayerView}

{view: View,layerView: LayerView}

Event Details

layerview-create

Fires after the layer's LayerView is created and rendered in a view.

Properties:

view View The view in which the layerView was created.

layerView LayerView The LayerView rendered in the view representing the layer in layer.

See also:

• View.whenLayerView()

Example:

// This function will fire each time a layer view is created for this
// particular view.
layer.on("layerview-create", function(event){
  // The LayerView for the layer that emitted this event
  event.layerView;
});

layerview-destroy

Fires after the layer's LayerView is destroyed and no longer renders in a view.

Properties:

view View The view in which the layerView was destroyed.

layerView LayerView The destroyed LayerView representing the layer.