VisualVariable | API Reference | ArcGIS Maps SDK for JavaScript 4.31

The visual variable base class. See each of the subclasses that extend this class to learn how to create continuous data-driven thematic visualizations.

ColorVariable	SizeVariable	OpacityVariable	RotationVariable

See also

Property Overview

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

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Type	Summary	Class
String	The name of the class.	Accessor
String	The name of the numeric attribute field that contains the data values used to determine the color/opacity/size/rotation of each feature.	VisualVariable
Object	An object providing options for displaying the visual variable in the Legend.	VisualVariable
String	The visual variable type.	VisualVariable
String	An Arcade expression following the specification defined by the Arcade Visualization Profile.	VisualVariable
String	The title identifying and describing the associated Arcade expression as defined in the valueExpression property.	VisualVariable

Property Details

declaredClass Inherited Property declaredClass Stringreadonly Inherited from Accessor

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

field Property field String

The name of the numeric attribute field that contains the data values used to determine the color/opacity/size/rotation of each feature.

legendOptions Property legendOptions Objectautocast

An object providing options for displaying the visual variable in the Legend.

Properties: showLegend Boolean|null|undefined

Indicates whether to show the visual variable in the legend.

title String|null|undefined

The title describing the visualization of the visual variable in the Legend. This takes precedence over a field alias or valueExpressionTitle.

type Property type Stringreadonly

The visual variable type.

Possible Values:"color" |"opacity" |"rotation" |"size"

valueExpression Property valueExpression String

An Arcade expression following the specification defined by the Arcade Visualization Profile. Expressions in visual variables may reference field values using the $feature profile variable and must return a number.

The values returned from this expression are the data used to drive the visualization as defined in the stops. This takes precedence over field. Therefore, this property is typically used as an alternative to field in visual variables.

See also

Arcade - Visualization Profile

valueExpressionTitle Property valueExpressionTitle String

The title identifying and describing the associated Arcade expression as defined in the valueExpression property. This is displayed as the title of the corresponding visual variable in the Legend in the absence of a provided title in the legendOptions property.

Method Overview

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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
*	Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product.	VisualVariable
Boolean	Returns true if a named group of handles exist.	Accessor
	Removes a group of handles owned by the object.	Accessor
Object	Converts an instance of this class to its ArcGIS portal JSON representation.	VisualVariable

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.

fromJSON Method fromJSON(json){*}static

Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product. 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.

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");
}

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");

toJSON Method toJSON(){Object}

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

Returns

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