ExpressionInfo | References | ArcGIS Maps SDK for JavaScript

import ExpressionInfo from "@arcgis/core/form/ExpressionInfo.js";

Inheritance:: ExpressionInfo→Accessor

Since: ArcGIS Maps SDK for JavaScript 4.16

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 FormTemplate.elements are contained within a formTemplate set directly on either a FeatureForm.formTemplate or FeatureLayer.formTemplate.

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 FeatureForm.map property when instantiating a FeatureForm widget and using expressions that use the $map variable.

See also

Constructors

Constructor

Parameters

Parameter	Type	Description	Required
properties	`ExpressionInfoProperties`

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

Properties

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

Property	Type	Class
`declaredClass` readonly inherited	`string`	Accessor
`expression`	`string`
`name`	`string`
`returnType`	`FormExpressionReturnType`
`title`	`string \| null \| undefined`

declaredClass

readonlyinherited Property

Type: string

Inherited from: Accessor

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

expression

Property

Type: 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

Type: 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

Type: FormExpressionReturnType

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.

See also

Default value: "boolean"

title

Property

Type: string | null | undefined

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

Example

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

Methods

Method	Signature	Class
`fromJSON` inherited static	`fromJSON(json: any): any`	JSONSupportMixin
`clone`	`clone(): ExpressionInfo`
`toJSON` inherited	`toJSON(): any`	JSONSupportMixin

fromJSON

inheritedstatic Method

Signature: fromJSON (json: any): any

Inherited from: JSONSupportMixin

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.

Parameters

Parameter	Type	Description	Required
json	`any`	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: any
Returns a new instance of this class.

clone

Method

Signature: clone (): ExpressionInfo

Creates a deep clone of the ExpressionInfo class.

Returns: ExpressionInfo
A deep clone of the ExpressionInfo instance.

toJSON

inherited Method

Signature: toJSON (): any

Inherited from: JSONSupportMixin

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

Returns: any
The ArcGIS portal JSON representation of an instance of this class.