var 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"
});

Property Overview

Property Details

containerString|HTMLElement inherited

The ID or node representing the DOM element containing the widget. This property can only be set once.

declaredClassStringreadonly inherited

Since: ArcGIS API for JavaScript 4.7

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

destroyedBoolean inherited

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

iconClassStringreadonly

Since: ArcGIS API for JavaScript 4.7

The widget's default CSS icon class.

idString inherited

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.

labelStringreadonly

Since: ArcGIS API for JavaScript 4.7

The widget's default label.

listItemCreatedFunctionListItemCreatedHandler

Since: ArcGIS API for JavaScript 4.4

Specifies a function that accesses each ListItem. Each list item can be modified according to its modifiable properties. Actions can be added to list items using the actionsSections property of the ListItem.

See also:

• Sample - LayerList widget with actions

Example:

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

    // The event object contains properties of the
    // layer in the LayerList widget.
    var item = event.item;

    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"
      }]];
    }
  }
});

operationalItemsCollection<ListItem>readonly

A collection of ListItems representing operational layers.

See also:

• Layer.listMode

statusIndicatorsVisibleBoolean

Since: ArcGIS API for JavaScript 4.5

Option for enabling status indicators, which indicate whether or not each layer is loading resources.

Default Value:true

Example:

// disable status indicators for all layers listed in LayerList
layerList.statusIndicatorsVisible = false;

viewMapView|SceneView

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

viewModelLayerListViewModel

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.

Method Overview

Method Details

classes(classNames){String}inherited

Since: ArcGIS API for JavaScript 4.7

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

Prior to version 4.7, there were various approaches towards setting CSS classes. These were dependent upon variables, such as whether the classes were:

• a single static class,
• multiple static classes, or
• dynamic classes.

This helper method takes all of these approaches into account and simplifies it to use one single pattern to accommodate these multiple approaches.

Parameter:

classNames Array<(String|String[]|Object)> repeatable The class names.

Returns:

Type	Description
String	The computed class name.

See also:

• Guide - Widget development (rendering)

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

Destroys the widget instance.

emit(type, event)inherited

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.

hasEventListener(type){Boolean}inherited

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.

on(type, listener){Object}inherited

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);
});

own(handles)inherited

Widget teardown helper. Any handles added to it will be automatically removed when the widget is destroyed.

Parameter:

handles WatchHandle|WatchHandle[] Handles marked for removal once the widget is destroyed.

postInitialize()inherited

This method is primarily used by developers when implementing custom widgets. Executes after widget is ready for rendering.

render(){Object}inherited

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

Renders widget to the DOM immediately.

scheduleRender()inherited

This method is primarily used by developers when implementing custom widgets. Schedules widget rendering. This method is useful for changes affecting the UI.

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.

Type Definitions

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.

Event Overview

{action: ActionButton,ActionToggle,item: ListItem}

Event Details

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 An item associated with the action.