Element | API Reference | ArcGIS Maps SDK for JavaScript 4.30

Form elements define what should display within the FormTemplate elements. There are four specific element types:

The Element class is a read-only base class which has no constructor.

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.

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Type	Summary	Class
String	The name of the class.	Accessor
String	The element's description providing the purpose behind it.	Element
String	A string value containing the field alias.	Element
String	The type of form element to display.	Element
String	A reference to the name of an Arcade expression defined in the expressionInfos of the FormTemplate.	Element

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.

description Property description String

The element's description providing the purpose behind it.

label Property label String

A string value containing the field alias. This should not be used for referencing fields in Arcade expressions. Rather, the service fieldName should be referenced.

type Property type Stringreadonly

The type of form element to display. There are three element types.

Possible Value	Description
field	An individual field element that defines the field within a layer or form's `formTemplate`.
group	Contains a grouping of field elements.
relationship	A relationship element defines a relationship between layers and tables and how they participate in the FeatureForm.
text	A text element defines descriptive text in a FormTemplate.

Possible Values:"field" |"group" |"relationship" |"text"

visibilityExpression Property visibilityExpression String

A reference to the name of an Arcade expression defined in the expressionInfos of the FormTemplate.

When this expression evaluates to true, the element is displayed. When the expression evaluates to false the element is not displayed. If no expression is provided, the element is always displayed. Care must be taken when defining a visibility expression for a non-nullable field as to make certain the specified field has either 1) a default value, or 2) is made visible to the end user to enter a value before submitting the form.

The expression must follow the specification defined in the Form Calculation Profile. This expression references field values within an individual feature or in other layers and must return either a date, number, or string value.
The referenced expression must be defined in the form template's expressionInfos. It cannot be set inline within the element object.
Field and Group elements must be visible if the field or one of the grouped fields is required.

See also

Example

// Expression created within ExpressionInfos and is referenced in element
const expression = new ExpressionInfo({
  name: "alwaysHidden",
  expression: "false"
});

// Reference an already-defined visibilityExpression set within the ExpressionInfos
const fieldElement = new FieldElement({
  type: "field",
  fieldName: "inspemail",
  label: "Email address",
  visibilityExpression: "alwaysHidden"
});

formTemplate.expressionInfos = [ expression ];
formTemplate.elements = [ fieldElement ];

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.	Element
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.	Element

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.