BasemapLayerList | References | ArcGIS Maps SDK for JavaScript

import BasemapLayerList from "@arcgis/core/widgets/BasemapLayerList.js";

Inheritance:: BasemapLayerList→Widget→Accessor

Since: ArcGIS Maps SDK for JavaScript 4.13

The BasemapLayerList widget provides a way to display a list of Basemap layers and switch on/off their visibility. Base layers and reference layers are divided into separate sections. When editing is enabled, layers can be reordered by dragging and dropping between the lists and the title can be edited.

BasemapLayerList is very similar to our LayerList widget. See below samples for code inspiration:
Sample - LayerList widget
Sample - LayerList widget with actions

See also

BasemapLayerListViewModel

Example

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

Constructors

Constructor

Parameters

Parameter	Type	Description	Required
properties	`BasemapLayerListProperties`

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

Example

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

Properties

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

Property	Type	Class
`baseFilterPredicate`	`FilterPredicate \| null \| undefined`
`baseFilterText`	`string`
`baseItems` readonly	`Collection<ListItem>`
`baseListItemCreatedFunction`	`ListItemModifier \| null \| undefined`
`basemapTitle`	`string \| null \| undefined`
`catalogLayerList` readonly	`CatalogLayerList \| null \| undefined`
`catalogOptions`	`CatalogLayerListProperties \| null \| undefined`
`collapsed`	`boolean`
`container` inherited	`HTMLElement \| null \| undefined`	Widget
`declaredClass` readonly inherited	`string`	Accessor
`destroyed` readonly inherited	`boolean`	Widget
`dragEnabled`	`boolean`
`editingTitle`	`boolean`
`filterPlaceholder`	`string`
`headingLevel`	`HeadingLevel`
`icon`	`Icon["icon"]`
`id` inherited	`string`	Widget
`label`	`string`
`minFilterItems`	`number`
`referenceFilterPredicate`	`FilterPredicate \| null \| undefined`
`referenceFilterText`	`string`
`referenceItems` readonly	`Collection<ListItem>`
`referenceListItemCreatedFunction`	`ListItemModifier \| null \| undefined`
`selectedItems`	`Collection<ListItem>`
`selectionMode`	`"multiple" \| "none" \| "single" \| "single-persist"`
`uid` readonly inherited	`string`	IdentifiableMixin
`view`	`MapViewOrSceneView \| null \| undefined`
`viewModel`	`BasemapLayerListViewModel`
`visibilityAppearance`	`VisibilityAppearance`
`visible` inherited	`boolean`	Widget
`visibleElements`	`BasemapLayerListVisibleElements`

baseFilterPredicate

Property

Type: FilterPredicate | null | undefined

Since: ArcGIS Maps SDK for JavaScript 4.32

Specifies a function to handle filtering base layer list items.

Example

layerList.baseFilterPredicate = (item) => item.title.toLowerCase().includes("streets");

baseFilterText

Property

Type: string

Since: ArcGIS Maps SDK for JavaScript 4.29

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

See also

visibleElements.filter

Default value: ""

Example

reactiveUtils.watch(
  () => basemapLayerList.baseFilterText,
  (baseFilterText) => console.log(baseFilterText)
);

baseItems

readonly Property

Type: Collection<ListItem>

A collection of ListItems representing the Basemap.baseLayers.

baseListItemCreatedFunction

Property

Type: ListItemModifier | null | undefined

Specifies a function that accesses each ListItem representing a base layer. Each list item's modifiable properties can be updated within. Actions can be added to list items using the ListItem.actionsSections property of the ListItem.

Example

const bmLayerList = new BasemapLayerList({
  view: view,
  baseListItemCreatedFunction: (event) => {
    const baseListItem = event.item;
    if(baseListItem.title === "World Imagery_01"){
      // clean up title
      baseListItem.title = "World Imagery";
      // open the baseList item
      baseListItem.open = true;
    }
  }
})

basemapTitle

Property

Type: string | null | undefined

The current basemap's title.

catalogLayerList

readonly Property

Type: CatalogLayerList | null | undefined

Since: ArcGIS Maps SDK for JavaScript 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 BasemapLayerList widget. This property is set when a catalog layer's dynamic group layer is expanded in the BasemapLayerList. 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 CatalogLayerList.@trigger-action event and managing selections in catalog layers.

CatalogLayerList

See also

catalogOptions

Example

// Use reactiveUtils to respond to the basemapLayerList.catalogLayerList "trigger-action" event
reactiveUtils.on(
  () => basemapLayerList.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 basemapLayerList.catalogLayerList
reactiveUtils.watch(
  () => basemapLayerList.catalogLayerList?.selectedItems.at(0)?.layer,
  (layer) => {
    // When a layer is selected log out its title
    if (layer) {
      console.log(layer.title);
    }
  }
);

catalogOptions

Property

Type: CatalogLayerListProperties | null | undefined

Since: ArcGIS Maps SDK for JavaScript 4.30

CatalogLayer specific properties. Catalog layers will display their dynamicGroupLayer as an expandable catalogLayerList in the BasemapLayerList 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.

See also

catalogLayerList

Example

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

collapsed

Property

Type: boolean

Since: ArcGIS Maps SDK for JavaScript 4.29

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

See also

visibleElements.collapseButton

Default value: false

Example

basemapLayerList.collapsed = true;

container

autocast inherited Property

Type: HTMLElement | null | undefined

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

readonlyinherited Property

Type: string

Inherited from: Accessor

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

destroyed

readonlyinherited Property

Type: boolean

Inherited from: Widget

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

dragEnabled

Property

Type: boolean

Since: ArcGIS Maps SDK for JavaScript 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.

Default value: false

Example

basemapLayerList.dragEnabled = true;

editingTitle

Property

Type: boolean

Since: ArcGIS Maps SDK for JavaScript 4.29

Indicates whether the form to edit the basemap's title is currently visible. Any edits made will only be shown locally and will not be saved.

See also

visibleElements.editTitleButton

Default value: false

Example

basemapLayerList.editingTitle = true;

filterPlaceholder

Property

Type: string

Since: ArcGIS Maps SDK for JavaScript 4.29

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

See also

visibleElements.filter

Default value: ""

Example

basemapLayerList.filterPlaceholder = "Filter layers";

headingLevel

Property

Type: HeadingLevel

Since: ArcGIS Maps SDK for JavaScript 4.20

Indicates the heading level to use for the widget title (i.e. "Navigation"). By default, the basemap's title is rendered as a level 2 heading (e.g. <h2>Navigation</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.

See also

Heading Elements

Default value: 2

Example

// the widget title will render as an <h3>
basemapLayerList.headingLevel = 3;

icon

autocast Property

Type: Icon["icon"]

Since: ArcGIS Maps SDK for JavaScript 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).

See also

Default value: "layers"

id

inherited Property

Type: 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

autocast Property

Type: string

The widget's default label.

minFilterItems

Property

Type: number

Since: ArcGIS Maps SDK for JavaScript 4.29

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

See also

visibleElements.filter

Default value: 10

Example

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

referenceFilterPredicate

Property

Type: FilterPredicate | null | undefined

Since: ArcGIS Maps SDK for JavaScript 4.32

Specifies a function to handle filtering reference layer list items.

Example

layerList.referenceFilterPredicate = (item) => item.title.toLowerCase().includes("streets");

referenceFilterText

Property

Type: string

Since: ArcGIS Maps SDK for JavaScript 4.29

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

See also

visibleElements.filter

Default value: ""

Example

reactiveUtils.watch(
  () => basemapLayerList.referenceFilterText,
  (referenceFilterText) => console.log(referenceFilterText)
);

referenceItems

readonly Property

Type: Collection<ListItem>

A collection of ListItems representing the Basemap.referenceLayers.

referenceListItemCreatedFunction

Property

Type: ListItemModifier | null | undefined

Specifies a function that accesses each ListItem representing a reference layer. Each list item's modifiable properties can be updated within. Actions can be added to list items using the ListItem.actionsSections.

Example

let bmLayerList = new BasemapLayerList({
  view: view,
  referenceListItemCreatedFunction: (event) => {
    referenceListItem = event.item;
    if(referenceListItem.title === "World Imagery_01_reference_layer"){
      // clean up title
      referenceListItem.title = "Reference layer";
      // open the baseList item
      referenceListItem.open = true;
    }
  }
})

selectedItems

autocast Property

Type: Collection<ListItem>

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

See also

selectionMode

selectionMode

Property

Type: "multiple" | "none" | "single" | "single-persist"

Since: ArcGIS Maps SDK for JavaScript 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.

See also

selectedItems

Default value: "none"

Example

basemapLayerList.selectionMode = "multiple";

uid

readonlyinherited Property

Type: string

Inherited from: IdentifiableMixin

Since: ArcGIS Maps SDK for JavaScript 4.33

An automatically generated unique identifier assigned to the instance. The unique id is generated each time the application is loaded.

view

Property

Type: MapViewOrSceneView | null | undefined

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

viewModel

autocast Property

Type: BasemapLayerListViewModel

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

visibilityAppearance

Property

Type: VisibilityAppearance

Since: ArcGIS Maps SDK for JavaScript 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.

Default value: "default"

Example

basemapLayerList.visibilityAppearance = "checkbox";

visible

inherited Property

Type: 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 DefaultUI, 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

autocast Property

Type: BasemapLayerListVisibleElements

Since: ArcGIS Maps SDK for JavaScript 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

basemapLayerList.visibleElements = {
  baseLayers: false,
  closeButton: false,
  collapseButton: true,
  editTitleButton: true,
  errors: true,
  filter: true,
  heading: true,
  referenceLayers: false,
  statusIndicators: true
};

Methods

Method	Signature	Class
`classes` inherited	`classes(...classNames: ((string \| null \| undefined) \| ((string[] \| Record<string, boolean>) \| null \| undefined) \| false \| null \| undefined)[]): string`	Widget
`destroy` inherited	`destroy(): void`	Widget
`emit` inherited	`emit<Type extends EventNames<this>>(type: Type, event?: this["@eventTypes"][Type]): boolean`	EventedMixin
`hasEventListener` inherited	`hasEventListener<Type extends EventNames<this>>(type: Type): boolean`	EventedMixin
`isFulfilled` inherited	`isFulfilled(): boolean`	EsriPromiseMixin
`isRejected` inherited	`isRejected(): boolean`	EsriPromiseMixin
`isResolved` inherited	`isResolved(): boolean`	EsriPromiseMixin
`on` inherited	`on<Type extends EventNames<this>>(type: Type, listener: EventedCallback<this["@eventTypes"][Type]>): ResourceHandle`	EventedMixin
`postInitialize` inherited	`postInitialize(): void`	Widget
`render` inherited	`render(): any \| null`	Widget
`renderNow` inherited	`renderNow(): void`	Widget
`scheduleRender` inherited	`scheduleRender(): void`	Widget
`triggerAction`	`triggerAction(action: Action, item: ListItem): void`
`when` inherited	`when<TResult1 = this, TResult2 = never>(onFulfilled?: OnFulfilledCallback<this, TResult1> \| null \| undefined, onRejected?: OnRejectedCallback<TResult2> \| null \| undefined): Promise<TResult1 \| TResult2>`	EsriPromiseMixin

classes

inherited Method

Signature: classes (...classNames: ((string | null | undefined) | ((string[] | Record<string, boolean>) | null | undefined) | false | null | undefined)[]): string

Inherited from: Widget

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

Parameters

Parameter	Type	Description	Required
classNames	`((string \| null \| undefined) \| ((string[] \| Record<string, boolean>) \| null \| undefined) \| false \| null \| undefined)[]`	The class names.

Returns: 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

Signature: destroy (): void

Inherited from: Widget

Destroys the widget instance.

Returns: void

emit

inherited Method

Signature: emit <Type extends EventNames<this>>(type: Type, event?: this["@eventTypes"][Type]): boolean

Type parameters: <Type extends EventNames<this>>

Inherited from: EventedMixin

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

Parameters

Parameter	Type	Description	Required
type	`Type`	The name of the event.
event	`this["@eventTypes"][Type]`	The event payload.

Returns: boolean
true if a listener was notified

hasEventListener

inherited Method

Signature: hasEventListener <Type extends EventNames<this>>(type: Type): boolean

Type parameters: <Type extends EventNames<this>>

Inherited from: EventedMixin

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

Parameters

Parameter	Type	Description	Required
type	`Type`	The name of the event.

Returns: boolean
Returns true if the class supports the input event.

isFulfilled

inherited Method

Signature: isFulfilled (): boolean

Inherited from: EsriPromiseMixin

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: boolean
Indicates whether creating an instance of the class has been fulfilled (either resolved or rejected).

isRejected

inherited Method

Signature: isRejected (): boolean

Inherited from: EsriPromiseMixin

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

Returns: boolean
Indicates whether creating an instance of the class has been rejected.

isResolved

inherited Method

Signature: isResolved (): boolean

Inherited from: EsriPromiseMixin

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

Returns: boolean
Indicates whether creating an instance of the class has been resolved.

on

inherited Method

Signature: on <Type extends EventNames<this>>(type: Type, listener: EventedCallback<this["@eventTypes"][Type]>): ResourceHandle

Type parameters: <Type extends EventNames<this>>

Inherited from: EventedMixin

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

Parameters

Parameter	Type	Description	Required
type	`Type`	An event or an array of events to listen for.
listener	`EventedCallback<this["@eventTypes"][Type]>`	The function to call when the event fires.

Returns

ResourceHandle

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

Signature: postInitialize (): void

Inherited from: Widget

Executes after widget is ready for rendering.

Returns: void

render

inherited Method

Signature: render (): any | null

Inherited from: Widget

This method is implemented by subclasses for rendering.

Returns: any | null
The rendered virtual node.

renderNow

inherited Method

Signature: renderNow (): void

Inherited from: Widget

Renders widget to the DOM immediately.

Returns: void

scheduleRender

inherited Method

Signature: scheduleRender (): void

Inherited from: Widget

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

Returns: void

triggerAction

Method

Signature: triggerAction (action: Action, item: ListItem): void

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

Parameters

Parameter	Type	Description	Required
action	`Action`	The action to execute.
item	`ListItem`	An item associated with the action.

Returns: void

when

inherited Method

Signature: when <TResult1 = this, TResult2 = never>(onFulfilled?: OnFulfilledCallback<this, TResult1> | null | undefined, onRejected?: OnRejectedCallback<TResult2> | null | undefined): Promise<TResult1 | TResult2>

Type parameters: <TResult1 = this, TResult2 = never>

Inherited from: EsriPromiseMixin

when() may be leveraged once an instance of the class is created. This method takes two input parameters: an 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

Parameter	Type	Description	Required
onFulfilled	`OnFulfilledCallback<this, TResult1> \| null \| undefined`	The function to call when the promise resolves.
onRejected	`OnRejectedCallback \| null \| undefined`	The function to execute when the promise fails.

Returns: Promise<TResult1 | TResult2>
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
});

Events

Name	Type
`trigger-action` inherited	CustomEvent<LayerListViewModelTriggerActionEvent>

trigger-action

inherited Event

trigger-action: CustomEvent<LayerListViewModelTriggerActionEvent>

Inherited from: LayerListViewModelEvents

Emitted when the user clicks an action or action toggle in a layer list. Use this event to run custom logic when a specific action is triggered.

See also

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