ExpressionInfo | API Reference | ArcGIS Maps SDK for JavaScript 4.31

The ExpressionInfo class defines the makeup of visibility expressions, required expressions, editable expressions, and value expressions. Visibility expressions are available on field, group, and relationship elements. These elements are contained within a formTemplate set directly on either a FeatureForm or FeatureLayer.

All of the Arcade expressions referenced above, excluding value expressions, must follow the specification defined in the Form Constraint Profile. This profile may reference field values using the $feature variable and the expression must return true or false.

Value expressions must follow the specification defined in the Form Calculation Profile. It may reference field values within an individual $feature or in other layers and must return either a date, number, or string value. Once the expression evaluates, the form's field value updates to the expressions' result.

It is required to set the map property when instantiating a FeatureForm widget and using expressions that use the $map variable.

See also

Constructors

ExpressionInfo Constructor new ExpressionInfo(properties)

Parameter

properties Object

optional

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

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	An Arcade expression following the specification defined by the Form Constraint or Form Calculation profiles.	ExpressionInfo
String	The name of the expression.	ExpressionInfo
String	Indicates the return type of the Arcade expression.	ExpressionInfo
String	The title used to describe the value returned by the expression.	ExpressionInfo

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.

expression Property expression String

An Arcade expression following the specification defined by the Form Constraint or Form Calculation profiles. Visibility expressions, required expressions, and editable expressions follow the specification defined in the Form Constraint profile. These expressions may reference field values using the $feature profile variable and must return either true or false.

Value expressions adhere to the specification defined in the Form Calculation profile. The available profile variables when working with value expressions extend beyond just $feature since it is also possible to access values beyond the individual feature that is being displayed.

See also

Example

// Sets the visibility of a field in the form template only if the date is within the last 24 hours.
expressionInfo.expression = "IIF(DateDiff(Now(), $feature.incident_date, 'hours') < 24)";

name Property name String

The name of the expression. Set this name to the visibility expression, required expression, editable expression, and/or value expression properties of its respective elements.

Example

expressionInfo.name = "withinRange";

returnType Property returnType String

Indicates the return type of the Arcade expression. In FeatureForm expressions, the returnType can be boolean, date, number or string. This is dependant upon the type of expression used. For example, visibility expressions, required expressions, and editable expressions only return a boolean, whereas value expressions return either date, number, or string.

Possible Values:"boolean" |"date" |"number" |"string"

See also

title Property title String

The title used to describe the value returned by the expression.

Example

expressionInfo.title = "Did the incident occur within the last 24 hours?";

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

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.

clone Method clone(){ExpressionInfo}

Creates a deep clone of the ExpressionInfo class.

Returns

Type	Description
ExpressionInfo	A deep clone of the ExpressionInfo instance.

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.