// in this case the portalItem has to be a webmap
var basemap = new Basemap({
  portalItem: {
    id: "8dda0e7b5e2d4fafa80132d59122268c"  // WGS84 Streets Vector webmap
  }
});

// or create the basemap from a well known ID
Basemap.fromId("topo");

// or create from a third party source
var basemap = new Basemap({
  baseLayers: [
    new WebTileLayer(...)
  ],
  referenceLayers: [
    new WebTileLayer(...)
  ],
});

// create a basemap from a dynamic mapserver
var basemap = new Basemap({
  baseLayers: [
    new MapImageLayer({
      url: "url to your dynamic MapServer",
      title: "Basemap"
    })
  ],
  title: "basemap",
  id: "basemap"
});

var map = new Map({
  basemap: basemap
});

// create a TileInfo instance using the default settings and
// pass its resulting LOD's to a MapView's constraints
var view = new MapView({
  container: "viewDiv",
  map: map,
  constraints: {
    lods: TileInfo.create().lods
  }
});

Property Overview

Property Details

baseLayers Collection<Layer>autocast

A collection of tile layers that make up the basemap's features.

declaredClass Stringreadonly inherited

Since: ArcGIS API for JavaScript 4.7

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

id String

An identifier used to refer to the basemap when referencing it elsewhere.

Example:

var customBasemap = new Basemap({
  baseLayers: [layers],
  title: "Custom Basemap",
  id: "myBasemap"
});

loaded Booleanreadonly

Indicates whether the basemap instance has loaded. When true, all the properties of the object can be accessed.

Default Value:false

loadError Errorreadonly

The Error object returned if an error occurred while loading.

Default Value:null

loadStatus Stringreadonly

Represents the status of a load operation.

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

Possible Values:"not-loaded"|"loading"|"failed"|"loaded"

Default Value:not-loaded

loadWarnings Object[]readonly

A list of warnings which occurred while loading.

portalItem PortalItemautocast

The portal item.

referenceLayers Collection<Layer>

A collection of tiled reference layers for displaying labels.

spatialReference SpatialReferenceautocast

Since: ArcGIS API for JavaScript 4.14

The spatial reference of the Basemap. This indicates the Projected Coordinate System or the Geographic Coordinate System used to locate geographic features in the map.

When using an Esri basemap, the default spatial reference is Web Mercator Auxiliary Sphere.

thumbnailUrl String

The URL pointing to an image that represents the basemap. When using a custom basemap in the BasemapToggle widget, the image specified here will display in the widget. When the user clicks the image, the map's basemap will update to the basemap associated with the image.

See also:

• Sample - Custom basemap

title String

The title of the basemap.

Method Overview

Method Details

cancelLoad()

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

clone(){Basemap}

Creates a deep clone of this object.

Returns:

Type	Description
Basemap	A deep clone of the Basemap instance that invoked this method.

fromId(id){Basemap}static

Creates a new basemap instance from a well known basemap ID. See Map.basemap for a list of possible values.

Parameter:

id String The basemap ID.

Returns:

Type	Description
Basemap	A new Basemap instance.

Examples:

var streetsBasemap = Basemap.fromId("streets");

var nightBasemap = Basemap.fromId("streets-night-vector");

fromJSON(json){*}static

Creates a new instance of this class and initializes it with values from a JSON object generated from a product in the ArcGIS platform. The object passed into the input json parameter often comes from a response to a query operation in the REST API or a toJSON() method from another ArcGIS product. See the Using fromJSON() topic in the Guide for details and examples of when and how to use this function.

Parameter:

json Object A JSON representation of the instance in the ArcGIS format. See the ArcGIS REST API documentation for examples of the structure of various input JSON objects.

Returns:

Type	Description
*	Returns a new instance of this class.

isFulfilled(){Boolean}

isFulfilled() may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected). If it is fulfilled, true will be returned.

Returns:

Type	Description
Boolean	Indicates whether creating an instance of the class has been fulfilled (either resolved or rejected).

isRejected(){Boolean}

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

Returns:

Type	Description
Boolean	Indicates whether creating an instance of the class has been rejected.

isResolved(){Boolean}

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

Returns:

Type	Description
Boolean	Indicates whether creating an instance of the class has been resolved.

load(signal){Promise}

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

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

It's possible to provide a signal to stop being interested into a Loadable instance load status. When the signal is aborted, the instance does not stop its loading process, only cancelLoad can abort it.

Parameter:

signal AbortSignal optional Signal object that can be used to abort the asynchronous task. The returned promise will be rejected with an Error named AbortError when an abort is signaled. See also AbortController for more information on how to construct a controller that can be used to deliver abort signals.

Returns:

Type	Description
Promise	Resolves when the resources have loaded.

loadAll(){Promise<Basemap>}

Since: ArcGIS API for JavaScript 4.9

Loads all the externally loadable resources associated with the basemap. For the basemap this will load all the base layers and reference layers.

Returns:

Type	Description
Promise<Basemap>	Resolves when all the loadable resources have been loaded. Rejects if at least one of the loadable resources failed to load.

See also:

• load

Example:

// Load all resources but ignore if one or more of them failed to load
basemap.loadAll()
  .catch(function(error) {
    // Ignore any failed resources
  })
  .then(function() {
    console.log("All loaded");
  });

toJSON(){Object}

Converts an instance of this class to its ArcGIS portal JSON representation. See the Using fromJSON() topic in the Guide for more information.

Returns:

Type	Description
Object	The ArcGIS portal JSON representation of an instance of this class.

when(callback, errback){Promise}

Since: ArcGIS API for JavaScript 4.6

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

Parameters:

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

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

Returns:

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

Example:

// Although this example uses MapView, any class instance that is a promise may use then() in the same way
var view = new MapView();
view.when(function(){
  // This function will execute once the promise is resolved
}, function(error){
  // This function will execute if the promise is rejected due to an error
});