LayerList | API Reference | ArcGIS Maps SDK for JavaScript 4.30

The LayerList widget provides a way to display a list of layers, and switch on/off their visibility. The ListItem API provides access to each layer's properties, allows the developer to configure actions related to the layer, and allows the developer to add content to the item related to the layer.

To hide layers in the map from the LayerList widget, you must set the listMode property on the desired layers to hide.

Notes

When a KnowledgeGraphLayer is present in the map, the LayerList widget will display the knowledge graph layer tables as a tableList ListItem.
When a CatalogLayer is present in the map, the LayerList widget will display the catalog layer dynamicGroupLayer in a catalogLayerList ListItem.

See also

Example

let layerList = new LayerList({
  view: view
});
// Adds widget below other elements in the top left corner of the view
view.ui.add(layerList, {
  position: "top-left"
});

Constructors

LayerList Constructor new LayerList(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
const layerlist = new LayerList({
  view
});

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.

Show inherited properties

Hide inherited properties

Type	Summary	Class
CatalogLayerList\|null\|undefined	The CatalogLayerList widget instance that displays a catalog layer's dynamic group layer.	LayerList
Object\|null\|undefined	CatalogLayer specific properties.	LayerList
Boolean	Indicates whether the widget is collapsed.	LayerList
String\|HTMLElement	The ID or node representing the DOM element containing the widget.	Widget
String	The name of the class.	Accessor
Boolean	Indicates whether list items may be reordered within the list by dragging and dropping.	LayerList
String	Placeholder text used in the filter input if visibleElements.filter is true.	LayerList
String	The value of the filter input if visibleElements.filter is true.	LayerList
Number	Indicates the heading level to use for the heading of the widget.	LayerList
String	Icon which represents the widget.	LayerList
String	The unique ID assigned to the widget when the widget is created.	Widget
Object\|null\|undefined	KnowledgeGraphLayer specific properties.	LayerList
String	The widget's default label.	LayerList
ListItemCreatedHandler\|null\|undefined	A function that executes each time a ListItem is created.	LayerList
Number	The minimum number of list items required to enable drag and drop reordering with dragEnabled.	LayerList
Number	The minimum number of list items required to display the visibleElements.filter input box.	LayerList
Boolean	Indicates whether more than one list item may be selected by the user at a single time.	LayerList
Collection<ListItem>	A collection of ListItems representing operational layers.	LayerList
Collection<ListItem>	A collection of selected ListItems representing operational layers selected by the user.	LayerList
Boolean	Indicates whether list items may be selected by the user.	LayerList
String	Specifies the selection mode.	LayerList
TableList\|null\|undefined	The TableList widget instance that displays the tables associated with a KnowledgeGraphLayer.	LayerList
MapView\|SceneView\|null\|undefined	A reference to the MapView or SceneView.	LayerList
LayerListViewModel	The view model for this widget.	LayerList
String	Determines the icons used to indicate visibility.	LayerList
Boolean	Indicates whether the widget is visible.	Widget
VisibleElements	The visible elements that are displayed within the widget.	LayerList

Property Details

catalogLayerList Property catalogLayerList CatalogLayerList |null |undefinedreadonly Since: ArcGIS Maps SDK for JavaScript 4.30 LayerList since 4.2, catalogLayerList added at 4.30.

The CatalogLayerList widget instance that displays a catalog layer's dynamic group layer. The catalog layer list will be displayed as an expandable ListItem in the LayerList widget. This property is set when a catalog layer's dynamic group layer is expanded in the LayerList. Otherwise, it is null. This list item will only be displayed when catalog layers are loaded in the map and will be displayed as a child of the catalog layer. This property is useful for listening to the trigger-action event and managing selections in catalog layers.

CatalogLayerList

Default Value:null

See also

catalogOptions

Example

// Use reactiveUtils to respond to the layerList.catalogLayerList "trigger-action" event
reactiveUtils.on(
  () => layerList.catalogLayerList,
  "trigger-action",
  async (event) => {
    if (event.action.id === "add-layer") {
      // Get the parent catalog layer
      const parentCatalogLayer = catalogUtils.getCatalogLayerForLayer(event.item.layer);
      // Get the footprint from the parent catalog layer
      const footprint = parentCatalogLayer.createFootprintFromLayer(event.item.layer);
      // Get the layer from the footprint
      const layerFromFootprint = await parentCatalogLayer.createLayerFromFootprint(footprint);
      // Add the layer to the map
      map.add(layerFromFootprint);
    }
  }
);

// Use reactiveUtils to watch for a selected item in the layerList.catalogLayerList
reactiveUtils.watch(
  () => layerList.catalogLayerList?.selectedItems.at(0)?.layer,
  (layer) => {
    // When a layer is selected log out its title
    if (layer) {
      console.log(layer.title);
    }
  }
);

catalogOptions Property catalogOptions Object |null |undefined Since: ArcGIS Maps SDK for JavaScript 4.30 LayerList since 4.2, catalogOptions added at 4.30.

CatalogLayer specific properties. Catalog layers will display their dynamicGroupLayer as an expandable catalogLayerList in the LayerList widget. This list item will only be displayed when catalog layers with dynamic group layers are loaded in the map. These are the properties that are used to configure the catalogLayerList.

Properties

filterPlaceholder String

optional

Default Value:""

Placeholder text used in the filter input box.

listItemCreatedFunction ListItemCreatedHandler

optional

Default Value:null

A function that executes each time a ListItem is created.

minFilterItems Number

optional

Default Value:10

The minimum number of list items required to display the filter input box.

selectionMode String

optional

Default Value:"none"

The selection mode for the catalog layer list. See CatalogLayerList for more information.

visibilityAppearance String

optional

Default Value:"default"

Determines the icons used to indicate visibility. See CatalogLayerList for more information.

visibleElements Object

optional

Default Value:null

The visible elements that are displayed within the catalog layer list.

Specification: errors Boolean

optional
Default Value:true

Indicates whether to display errors in the catalog layer list.

filter Boolean

optional
Default Value:false

Indicates whether to display the filter input box in the catalog layer list.

statusIndicators Boolean

optional
Default Value:true

Indicates whether to display status indicators in the catalog layer list.

temporaryLayerIndicators Boolean

optional
Default Value:false

Indicates whether temporary layer indicators will be displayed. A temporary icon will be displayed on the near side of the layer title.

Default Value:null

See also

catalogLayerList

Example

const layerList = new LayerList({
  catalogOptions: {
    listItemCreatedFunction: (event) => {
      const { item } = event;
      item.actionsSections = [
        [
          {
            title: "Add layer to map",
            icon: "add-layer",
            id: "add-layer"
          }
        ]
      ];
    },
    selectionMode: "single",
    visibleElements: {
      filter: true
    }
  },
  view,
});

collapsed Property collapsed Boolean Since: ArcGIS Maps SDK for JavaScript 4.29 LayerList since 4.2, collapsed added at 4.29.

Indicates whether the widget is collapsed. When collapsed, only the collapse button and heading are displayed.

Default Value:false

See also

visibleElements.collapseButton

Example

layerList.collapsed = true;

container Inherited Property container String |HTMLElement Inherited from Widget

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.

dragEnabled Property dragEnabled Boolean Since: ArcGIS Maps SDK for JavaScript 4.29 LayerList since 4.2, dragEnabled added at 4.29.

Indicates whether list items may be reordered within the list by dragging and dropping. MapImageLayer sublayers can be reordered only within their parent MapImageLayer and can not be dragged out as a separate layer. Drag won't be enabled until the number of list items is equal to or greater than than the value set set in minDragEnabledItems.

Default Value:false

See also

minDragEnabledItems

Example

layerList.dragEnabled = true;

filterPlaceholder Property filterPlaceholder String Since: ArcGIS Maps SDK for JavaScript 4.29 LayerList since 4.2, filterPlaceholder added at 4.29.

Placeholder text used in the filter input if visibleElements.filter is true.

Default Value:""

See also

visibleElements.filter

Example

layerList.filterPlaceholder = "Filter layers";

filterText Property filterText String Since: ArcGIS Maps SDK for JavaScript 4.29 LayerList since 4.2, filterText added at 4.29.

The value of the filter input if visibleElements.filter is true.

Default Value:""

See also

visibleElements.filter

Example

reactiveUtils.watch(
  () => layerList.filterText,
  (filterText) => console.log(filterText)
);

headingLevel Property headingLevel Number Since: ArcGIS Maps SDK for JavaScript 4.29 LayerList since 4.2, headingLevel added at 4.29.

Indicates the heading level to use for the heading of the widget. By default, the heading is rendered as a level 2 heading (e.g., <h2>Layer List</h2>). Depending on the widget's placement in your app, you may need to adjust this heading for proper semantics. This is important for meeting accessibility standards.

Default Value:2

See also

visibleElements.heading

Example

layerList.headingLevel = 3;

icon Property icon String Since: ArcGIS Maps SDK for JavaScript 4.27 LayerList since 4.2, icon added at 4.27.

Icon which represents the widget. It is typically used when the widget is controlled by another one (e.g. in the Expand widget).

Default Value:"layers"

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.

knowledgeGraphOptions Property knowledgeGraphOptions Object |null |undefined Since: ArcGIS Maps SDK for JavaScript 4.30 LayerList since 4.2, knowledgeGraphOptions added at 4.30.

KnowledgeGraphLayer specific properties. Knowledge graph layers will display sublayer tables as an expandable tableList in the LayerList widget. This tables list item will only be displayed when knowledge graph layers with tables are loaded in the map. These are the properties that are used to configure the tableList.

Properties

filterPlaceholder String

optional

Default Value:""

Placeholder text used in the filter input box.

listItemCreatedFunction ListItemCreatedHandler

optional

Default Value:null

A function that executes each time a ListItem is created.

minFilterItems Number

optional

Default Value:10

The minimum number of list items required to display the filter input box.

selectionMode String

optional

Default Value:"none"

The selection mode for the table list. See TableList for more information.

visibleElements Object

optional

Default Value:null

The visible elements that are displayed within the table list.

Specification: errors Boolean

optional
Default Value:true

Indicates whether to display errors in the table list.

filter Boolean

optional
Default Value:false

Indicates whether to display the filter input box in the table list.

statusIndicators Boolean

optional
Default Value:true

Indicates whether to display status indicators in the table list.

Default Value:null

See also

tableList

Example

layerList.knowledgeGraphOptions = {
  filterPlaceholder: "Filter tables",
  listItemCreatedFunction: (event) => {
    const { item } = event;
    item.actionsSections = [
      [
        {
          icon: "table",
          id: "open-table",
          title: "Show table"
        },
        {
          icon: "information",
          id: "information",
          title: "Show information"
        }
      ]
    ];
  },
  minFilterItems: 1,
  visibleElements: {
    errors: true,
    filter: true,
    statusIndicators: true
  }
}

label Property label String Since: ArcGIS Maps SDK for JavaScript 4.7 LayerList since 4.2, label added at 4.7.

The widget's default label.

listItemCreatedFunction Property listItemCreatedFunction ListItemCreatedHandler |null |undefined Since: ArcGIS Maps SDK for JavaScript 4.4 LayerList since 4.2, listItemCreatedFunction added at 4.4.

A function that executes each time a ListItem is created. Use this function to add actions and panels to list items, and to override the default settings of a list item. Actions can be added to list items using the actionsSections property of the ListItem.

Default Value:null

See also

Sample - LayerList widget with actions

Example

let layerList = new LayerList({
  view: view,
  // executes for each ListItem in the LayerList
  listItemCreatedFunction: async function (event) {

    // The event object contains properties of the
    // layer in the LayerList widget.

    let item = event.item;

    // Wait for the layer to load and the item title to become available
    await item.layer.when();

    if (item.title === "US Demographics") {
      // open the list item in the LayerList
      item.open = true;
      // change the title to something more descriptive
      item.title = "Population by county";
      // set an action for zooming to the full extent of the layer
      item.actionsSections = [[{
        title: "Go to full extent",
        className: "esri-icon-zoom-out-fixed",
        id: "full-extent"
      }]];
    }
  }
});

minDragEnabledItems Property minDragEnabledItems Number Since: ArcGIS Maps SDK for JavaScript 4.29 LayerList since 4.2, minDragEnabledItems added at 4.29.

The minimum number of list items required to enable drag and drop reordering with dragEnabled.

Default Value:2

See also

dragEnabled

Example

layerList.dragEnabled = true;
layerList.minDragEnabledItems = 5;

minFilterItems Property minFilterItems Number Since: ArcGIS Maps SDK for JavaScript 4.29 LayerList since 4.2, minFilterItems added at 4.29.

The minimum number of list items required to display the visibleElements.filter input box.

Default Value:10

See also

visibleElements.filter

Example

layerList.visibleElements.filter = true;
layerList.minFilterItems = 5;

multipleSelectionEnabled Property multipleSelectionEnabled Boolean Deprecated since 4.29. Use selectionMode instead.

Indicates whether more than one list item may be selected by the user at a single time. You must first set selectionEnabled to true for this property to have an effect on the widget.

Selected items are available in the selectedItems property.

Default Value:false

See also

selectionEnabled
selectedItems

Example

layerList.selectionEnabled = true;
layerList.multipleSelectionEnabled = true;

operationalItems Property operationalItems Collection<ListItem>readonly

A collection of ListItems representing operational layers. To hide layers from the LayerList widget, set the listMode property on the layer(s) to hide.

See also

Layer.listMode

selectedItems Property selectedItems Collection<ListItem>

A collection of selected ListItems representing operational layers selected by the user.

See also

selectionMode

selectionEnabled Property selectionEnabled Boolean Deprecated since 4.29. Use selectionMode and dragEnabled instead.

Indicates whether list items may be selected by the user. Selected items may be reordered in the list by dragging gestures with the mouse or touch screen, or with arrow keys on the keyboard.

Selected items are available in the selectedItems property.

Default Value:false

See also

selectedItems

Example

layerList.selectionEnabled = true;

selectionMode Property selectionMode String Since: ArcGIS Maps SDK for JavaScript 4.29 LayerList since 4.2, selectionMode added at 4.29.

Specifies the selection mode. Selected items are available in the selectedItems property.

Value	Description
multiple	Allows any number of items to be selected at once. This is useful when you want to apply an operation to multiple items at the same time.
none	Disables selection. Use this when you want to prevent selecting items.
single	Allows only one item to be selected at a time. If another item is selected, the previous selection is cleared. This is useful when you want to ensure that a maximum of one item is selected at a time.
single-persist	Allows only one item to be selected at a time and prevents de-selection. Once an item is selected, it remains selected until another item is selected. This is useful when you want to ensure that there is always exactly one selected item.

Possible Values:"multiple" |"none" |"single" |"single-persist"

Default Value:"none"

See also

selectedItems

Example

layerList.selectionMode = "multiple";

tableList Property tableList TableList |null |undefinedreadonly Since: ArcGIS Maps SDK for JavaScript 4.30 LayerList since 4.2, tableList added at 4.30.

The TableList widget instance that displays the tables associated with a KnowledgeGraphLayer. The table list will be displayed as an expandable ListItem in the LayerList widget. This property is set when a knowledge graph layer's tables ListItem is expanded in the LayerList. Otherwise, it is null. This list item will only be displayed when knowledge graph layers with tables are loaded in the map and will be displayed as a child of the knowledge graph layer. This property is useful for listening to the trigger-action event and managing selections in knowledge graph tables.

tableList

Default Value:null

See also

knowledgeGraphOptions

Example

// Use reactiveUtils to respond to the layerList.tableList "trigger-action" event
reactiveUtils.on(
  () => layerList.tableList,
  "trigger-action",
  (event) => {
    if (event.action.id === "open-table") {
      // Open the table in the FeatureTable widget
      featureTable.layer = event.item.layer;
    }
  }
);

// Use reactiveUtils to watch for a selected item in the layerList.tableList
reactiveUtils.watch(
  () => layerList.tableList?.selectedItems.at(0)?.layer,
  (layer) => {
    // When a layer is selected log out its title
    if (layer) {
       console.log(layer.title);
    }
  }
);

view Property view MapView |SceneView |null |undefined

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

Default Value:null

viewModel Property viewModel LayerListViewModel

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 LayerListViewModel class to access all properties and methods on the widget.

visibilityAppearance Property visibilityAppearance String Since: ArcGIS Maps SDK for JavaScript 4.29 LayerList since 4.2, visibilityAppearance added at 4.29.

Determines the icons used to indicate visibility.

Value	Description	Example
default	Displays view icons on the far side. Icons are hidden except on hover or if they have keyboard focus. See view-visible and view-hide calcite icons.
checkbox	Displays checkbox icons on the near side. See check-square-f and square calcite icons.

Possible Values:"default" |"checkbox"

Default Value:"default"

Example

layerList.visibilityAppearance = "checkbox";

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;

visibleElements Property visibleElements VisibleElements Since: ArcGIS Maps SDK for JavaScript 4.15 LayerList since 4.2, visibleElements added at 4.15.

The visible elements that are displayed within the widget. This property provides the ability to turn individual elements of the widget's display on/off.

Example

layerList.visibleElements = {
  catalogLayerList: true,
  closeButton: false,
  collapseButton: true,
  errors: true,
  filter: true,
  heading: true,
  statusIndicators: true
};

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
	Adds one or more handles which are to be tied to the lifecycle of the widget.	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
	Triggers the trigger-action event and executes the given action or action toggle.	LayerList
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 Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, isFulfilled added at 4.19.

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 Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, isRejected added at 4.19.

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 Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, isResolved added at 4.19.

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);
});

own Inherited Method own(handleOrHandles) Inherited from Widget Since: ArcGIS Maps SDK for JavaScript 4.24 Widget since 4.2, own added at 4.24. Deprecated since 4.28 Use addHandles() instead.

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

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

this.own(handle); // Handle gets removed when the widget is destroyed.

Parameter

handleOrHandles WatchHandle|WatchHandle []

Handles marked for removal once the widget is destroyed.

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.

triggerAction Method triggerAction(action, item)

Triggers the trigger-action event and executes the given action or action toggle.

Parameters

action ActionButton|ActionToggle

The action to execute.

item ListItem

An item associated with the action.

when Inherited Method when(callback, errback){Promise} Inherited from Widget Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, when added at 4.19.

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`.

Example

// Although this example uses the BasemapGallery widget, any class instance that is a promise may use when() in the same way
let bmGallery = new BasemapGallery();
bmGallery.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
});

Type Definitions

ListItemCreatedHandler Type Definition ListItemCreatedHandler(event)

Function definition for the listItemCreatedFunction property. See the example snippet in the listItemCreatedFunction documentation for more details.

Parameters

event Object

An object containing a list item created by the LayerList.

Specification

item ListItem

A list item created by the LayerList. You can modify the properties of this item to customize the text, actions, panel content, and visibility of the list item. See the documentation for the listItemCreatedFunction for more details.

VisibleElements Type Definition VisibleElements Since: ArcGIS Maps SDK for JavaScript 4.15 LayerList since 4.2, VisibleElements added at 4.15.

The visible elements that are displayed within the widget. This provides the ability to turn individual elements of the widget's display on/off.

Properties: catalogLayerList Boolean

optional
Default Value:true

Since 4.30 Indicates whether to display the catalogLayerList.

closeButton Boolean

optional
Default Value:false

Since 4.29 Indicates whether to display a close button in the header.

collapseButton Boolean

optional
Default Value:false

Since 4.29 Indicates whether to display a collapse button in the header.

errors Boolean

optional
Default Value:false

Since 4.25 Indicates whether layer load errors will be displayed.

filter Boolean

optional
Default Value:false

Since 4.29 Indicates whether to display a filter input box when then number of list items is equal to or greater than the value set in minFilterItems, allowing users to filter layers by their title.

flow Boolean

optional
Default Value:true

Since 4.29 Determines whether the widget should be shown within its built-in flow component or if the flow component should be excluded. The widget will be displayed within its original flow component if set to true. The flow component will be omitted from the widget if set to false. To place the widget into an existing Calcite flow component, set this property to false.

heading Boolean

optional
Default Value:false

Since 4.29 Indicates whether to display the widget heading. The heading text is "Layer List". The heading level can be set with the headingLevel.

statusIndicators Boolean

optional
Default Value:true

Indicates whether the status indicators will be displayed.

temporaryLayerIndicators Boolean

optional
Default Value:false

Since 4.29 Indicates whether temporary layer indicators will be displayed for layers with layer.persistenceEnabled set to false. A temporary icon will be displayed on the near side of the layer title.

Event Overview

Name	Type	Summary	Class
	{action: ActionButton\|ActionToggle,item: ListItem}	Fires after the user clicks on an action or action toggle inside the LayerList widget.	LayerList

Event Details

trigger-action Event trigger-action

Fires after the user clicks on an action or action toggle inside the LayerList widget. This event may be used to define a custom function to execute when particular actions are clicked.

Properties: action ActionButton|ActionToggle

The action clicked by the user.

item ListItem

The ListItem associated with the action.