Field | References | ArcGIS Maps SDK for JavaScript

import Field from "@arcgis/core/layers/support/Field.js";

Inheritance:: Field→Accessor

Since: ArcGIS Maps SDK for JavaScript 4.0

Information about each field in a layer. Field objects must be constructed when creating a FeatureLayer from client-side graphics. This class allows you to define the schema of each field in the FeatureLayer. Note that you do not need to add fields to the constructor of a FeatureLayer loaded from a service since they are already defined by the service. See the sample below for more information about using this module.

See also

Example

// Each object in this array is autocast as
// an instance of esri/layers/support/Field
let fields = [
  {
    name: "ObjectID",
    alias: "ObjectID",
    type: "oid"
  }, {
    name: "title",
    alias: "title",
    type: "string"
  }, {
    name: "type",
    alias: "type",
    type: "string"
  }, {
    name: "mag",
    alias: "Magnitude",
    type: "double"
}];

// add the array of fields to a feature layer
// created from client-side graphics
featureLayer.set({
  fields: fields,
  objectIdField: "ObjectID"
});

Constructors

Constructor

Parameters

Parameter	Type	Description	Required
properties	`FieldProperties`

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
`alias`	`string \| null \| undefined`
`declaredClass` readonly inherited	`string`	Accessor
`defaultValue`	`string \| number \| null \| undefined`
`description`	`string \| null \| undefined`
`domain`	`DomainUnion \| null \| undefined`
`editable`	`boolean`
`length`	`number \| null \| undefined`
`name`	`string`
`nullable`	`boolean`
`type`	`FieldType`
`valueType`	`FieldValueType \| null \| undefined`

alias

Property

Type: string | null | undefined

The alias of the field.

declaredClass

readonlyinherited Property

Type: string

Inherited from: Accessor

Since: ArcGIS Maps SDK for JavaScript 4.7

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

defaultValue

Property

Type: string | number | null | undefined

Since: ArcGIS Maps SDK for JavaScript 4.9

The default value set for the field.

description

Property

Type: string | null | undefined

Since: ArcGIS Maps SDK for JavaScript 4.12

Contains information describing the purpose of each field.

See also

domain

autocast Property

Type: DomainUnion | null | undefined

The domain associated with the field. Domains are used to constrain the values allowed in a field. There are two types of domains: RangeDomain and CodedValueDomain.

Example

// print out the coded domain values when the layer is loaded
const layerView = await view.whenLayerView(featureLayer)
await reactiveUtils.whenOnce(() => !layerView.updating);

featureLayer.fields.forEach((field) => {
  if (!field.domain) {
    return;
  }

  let domain = field.domain
  console.log(field.name, domain.type, domain.name);

  if (domain.type === "coded-value"){
    domain.codedValues.forEach((codeValue) => {
      console.log("name:", codeValue.name, "code:", codeValue.code);
    });
  }
});

editable

Property

Type: boolean

Indicates whether the field is editable.

Default value: true

length

Property

Type: number | null | undefined

The field length.

name

Property

Type: string

The name of the field.

nullable

Property

Type: boolean

Indicates if the field can accept null values. Requires ArcGIS Server version 10.1 or greater.

Default value: true

type

Property

Type: FieldType

The data type of the field.

Notes

Support for big-integer, date-only, time-only and timestamp-offset fields was added in beta for FeatureLayer and MapImageLayer at version 4.28. The big-integer field type is in beta and may not be fully supported in the JavaScript SDK. The JavaScript SDK only supports safe integers that fall between -9007199254740991 (minimum) and 9007199254740991 (maximum). Numbers that fall outside of this range will be incorrect due to rounding, resulting in graphical or performance issues. For example, a calculation using Arcade expressions that results in a value exceeding these safe integers may be incorrect since rounding can occur. Web applications can only edit whole numbers between -9007199254740991 and 9007199254740991.

See also

ArcGIS field data types

valueType

Property

Type: FieldValueType | null | undefined

Since: ArcGIS Maps SDK for JavaScript 4.12

The types of values that can be assigned to a field. See the table below for a list of possible values.

Mode	Description
binary	Only one of two values are possible for each feature. Some examples include the following: `On or off`, `Yes or no`, `True or false`, or `Inhabited or vacant`.
coordinate	These fields store a geographic coordinate value such as x, y, z, latitude, or longitude.
count-or-amount	Integers (no decimal) that represent how many or how much there is of a specific attribute.
currency	Numeric values that represent a monetary value.
date-and-time	Values in this field store explicit dates and times or date references such as days of the week, months, or years.
description	Text that provides a longer description of the feature, more than just a name or title.
email-address	Text that represents an email address.
location-or-place-name	Values in this field represent a geographic location. Examples of values in such a field include a street address, city name, region, building name (such as A.K. Smiley Public Library), attraction name (such as Alameda County Fairgrounds or Cairngorms National Park), postal code, or country.
measurement	A number that reflects a characteristic that you can precisely measure.
name-or-title	Text that represents a name, title, label, or keyword for each feature.
none	No specified type.
ordered-or-ranked	The values in this field represent a feature's status in an ordered or ranked list. For example, a feature could be one of the following: `Small, medium, large`, `First, second, third, fourth`, or `Informational, warning, error, failure`.
percentage-or-ratio	Number values in this field reflect the relationship between different quantities.
phone-number	Text that represents a phone number.
type-or-category	Types or categories that group features based on common characteristics.
unique-identifier	The values in this field are used to positively distinguish one feature or entity from another.

See also

Methods

Method	Signature	Class
`fromJSON` inherited static	`fromJSON(json: any): any`	JSONSupportMixin
`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.

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.