BasemapLayerList

AMD: require(["esri/widgets/BasemapLayerList"], (BasemapLayerList) => { /* code goes here */ });
ESM: import BasemapLayerList from "@arcgis/core/widgets/BasemapLayerList.js";
Class: esri/widgets/BasemapLayerList
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

For information about gaining full control of widget styles, see the Styling topic.
See also
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

BasemapLayerList

Constructor
new BasemapLayerList(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 BasemapLayerList = new BasemapLayerList({
  view: view
});

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.
Show inherited properties Hide inherited properties
Name Type Summary Class
String

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

BasemapLayerList
Collection<ListItem>

A collection of ListItems representing the baseLayers.

BasemapLayerList
ListItemCreatedHandler

Specifies a function that accesses each ListItem representing a base layer.

BasemapLayerList
String

The current basemap's title.

BasemapLayerList
Boolean

Indicates whether the widget is collapsed.

BasemapLayerList
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.

BasemapLayerList
Boolean

Indicates whether the basemap’s title, layer order and layer grouping can be edited by the user.

BasemapLayerList
Boolean

Indicates whether the form to edit the basemap's title is currently visible.

BasemapLayerList
String

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

BasemapLayerList
Number

Indicates the heading level to use for the widget title (i.e.

BasemapLayerList
String

Icon which represents the widget.

Widget
String

The widget's default CSS icon class.

BasemapLayerList
String

The unique ID assigned to the widget when the widget is created.

Widget
String

The widget's default label.

BasemapLayerList
Number

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

BasemapLayerList
Boolean

Indicates whether more than one list item may be selected by the user at a single time.

BasemapLayerList
String

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

BasemapLayerList
Collection<ListItem>

A collection of ListItems representing the referenceLayers.

BasemapLayerList
ListItemCreatedHandler

Specifies a function that accesses each ListItem representing a reference layer.

BasemapLayerList
Collection<ListItem>

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

BasemapLayerList
String

Specifies the selection mode.

BasemapLayerList
MapView|SceneView

A reference to the MapView or SceneView.

BasemapLayerList
BasemapLayerListViewModel

The view model for this widget.

BasemapLayerList
String

Determines the icons used to indicate visibility.

BasemapLayerList
Boolean

Indicates whether the widget is visible.

Widget
VisibleElements

The visible elements that are displayed within the widget.

BasemapLayerList

Property Details

baseFilterText

Property
baseFilterText String
Since: ArcGIS Maps SDK for JavaScript 4.29 BasemapLayerList since 4.13, baseFilterText added at 4.29.

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

Default Value:""
See also
Example
reactiveUtils.watch(
  () => basemapLayerList.baseFilterText,
  (baseFilterText) => console.log(baseFilterText)
);

baseItems

Property
baseItems Collection<ListItem>readonly

A collection of ListItems representing the baseLayers.

baseListItemCreatedFunction

Property
baseListItemCreatedFunction ListItemCreatedHandler

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 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
basemapTitle String

The current basemap's title.

collapsed

Property
collapsed Boolean
Since: ArcGIS Maps SDK for JavaScript 4.29 BasemapLayerList since 4.13, 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
Example
basemapLayerList.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

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 BasemapLayerList since 4.13, 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.

Default Value:false
Example
basemapLayerList.dragEnabled = true;

editingEnabled

Property
editingEnabled Boolean
Deprecated since 4.29. Use selectionMode, visibleElements.editTitleButton, and dragEnabled instead.

Indicates whether the basemap’s title, layer order and layer grouping can be edited by the user. Any edits made will only be shown locally and will not be saved.

Default Value:false
Example
// to enable editing
basemapLayerList.editingEnabled = true;

editingTitle

Property
editingTitle Boolean
Since: ArcGIS Maps SDK for JavaScript 4.29 BasemapLayerList since 4.13, editingTitle added at 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.

Default Value:false
See also
Example
basemapLayerList.editingTitle = true;

filterPlaceholder

Property
filterPlaceholder String
Since: ArcGIS Maps SDK for JavaScript 4.29 BasemapLayerList since 4.13, filterPlaceholder added at 4.29.

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

Default Value:""
See also
Example
basemapLayerList.filterPlaceholder = "Filter layers";

headingLevel

Property
headingLevel Number
Since: ArcGIS Maps SDK for JavaScript 4.20 BasemapLayerList since 4.13, headingLevel added at 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.

Default Value:2
See also
Example
// the widget title will render as an <h3>
basemapLayerList.headingLevel = 3;

icon

Inherited
Property
icon String
Inherited from Widget
Since: ArcGIS Maps SDK for JavaScript 4.27 Widget 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:null
See also

iconClass

Property
iconClass String
Deprecated since 4.27. Use icon instead.

The widget's default CSS icon class.

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

The widget's default label.

minFilterItems

Property
minFilterItems Number
Since: ArcGIS Maps SDK for JavaScript 4.29 BasemapLayerList since 4.13, minFilterItems added at 4.29.

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

Default Value:10
See also
Example
basemapLayerList.visibleElements.filter = true;
basemapLayerList.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. Selected items are available in the selectedItems property.

Default Value:false
See also
Example
basemapLayerList.multipleSelectionEnabled = true;

referenceFilterText

Property
referenceFilterText String
Since: ArcGIS Maps SDK for JavaScript 4.29 BasemapLayerList since 4.13, referenceFilterText added at 4.29.

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

Default Value:""
See also
Example
reactiveUtils.watch(
  () => basemapLayerList.referenceFilterText,
  (referenceFilterText) => console.log(referenceFilterText)
);

referenceItems

Property
referenceItems Collection<ListItem>readonly

A collection of ListItems representing the referenceLayers.

referenceListItemCreatedFunction

Property
referenceListItemCreatedFunction ListItemCreatedHandler

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 actionsSections property of the ListItem.

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

Property
selectedItems Collection<ListItem>

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

See also

selectionMode

Property
selectionMode String
Since: ArcGIS Maps SDK for JavaScript 4.29 BasemapLayerList since 4.13, 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
Example
basemapLayerList.selectionMode = "multiple";

view

Property
view MapView|SceneView

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

viewModel

Property
viewModel 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
visibilityAppearance String
Since: ArcGIS Maps SDK for JavaScript 4.29 BasemapLayerList since 4.13, 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. visibilityAppearance-default
checkbox Displays checkbox icons on the near side. See check-square-f and square calcite icons. visibilityAppearance-checkbox

Possible Values:"default"|"checkbox"

Default Value:"default"
Example
basemapLayerList.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 BasemapLayerList since 4.13, 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
basemapLayerList.visibleElements = {
  baseLayers: false,
  closeButton: false,
  collapseButton: true,
  editTitleButton: true,
  errors: true,
  filter: true,
  heading: true,
  referenceLayers: false,
  statusIndicators: true
};

Method Overview

Show inherited methods Hide inherited methods
Name 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

This method is primarily used by developers when implementing custom widgets.

Widget

Removes a group of handles owned by the object.

Accessor
Object

This method is primarily used by developers when implementing custom widgets.

Widget

Renders widget to the DOM immediately.

Widget

This method is primarily used by developers when implementing custom widgets.

Widget

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

BasemapLayerList
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

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 dynamicIconClasses = {
    [css.myIcon]: this.showIcon,
    [css.greyIcon]: !this.showIcon
  };

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

destroy

Inherited
Method
destroy()
Inherited from Widget

Destroys the widget instance.

emit

Inherited
Method
emit(type, event){Boolean}
Inherited from Widget

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

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

This method is primarily used by developers when implementing custom widgets. 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 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
Method
renderNow()
Inherited from Widget

Renders widget to the DOM immediately.

scheduleRender

Inherited
Method
scheduleRender()
Inherited from Widget

This method is primarily used by developers when implementing custom widgets. 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

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 baseListItemCreatedFunction and referenceListItemCreatedFunction properties. See the example snippets in the documentations for those properties 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

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
baseLayers Boolean
optional
Default Value:true

Indicates whether to the base layers will be displayed.

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.

editTitleButton Boolean
optional
Default Value:false

Since 4.29 Indicates whether to display a button in the header to edit the basemap title.

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:true

Since 4.29 Indicates whether the widget displays a heading. The heading text is the title of the basemap. The heading level can be set with the headingLevel.

referenceLayers Boolean
optional
Default Value:true

Indicates whether to the reference layers will be displayed.

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 BasemapLayerList widget.

BasemapLayerList

Event Details

trigger-action

Event
trigger-action

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

Properties

The action clicked by the user.

item ListItem

The ListItem associated with the action.

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