// Each object in this array is autocast as
// an instance of esri/layers/support/Field
var 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"
});

Property Overview

Property Details

alias String

The display name for the field.

Default Value:null

declaredClass Stringreadonly inherited

Since: ArcGIS API for JavaScript 4.7

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

defaultValue Number|String|null|undefined

Since: ArcGIS API for JavaScript 4.9

The default value set for the field.

Default Value:undefined

description String

Since: ArcGIS API for JavaScript 4.12

Contains information describing the purpose of each field.

See also:

• Blog - Describing layer attributes with field descriptions

• Describe attribute fields - ArcGIS Online Help

domain Domain

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.

Default Value:null

Example:

// print out the coded domain values when the layer is loaded
view.whenLayerView(featureLayer).then(function(layerView) {
  layerView.watch("updating", function(value) {
    if (!value) {
      featureLayer.fields.forEach(function(field){
        if (field.domain){
          var domain = field.domain
          console.log(field.name, domain.type, domain.name);
          if (domain.type === "coded-value"){
            domain.codedValues.forEach(function(codeValue){
              console.log("name:", codeValue.name, "code:", codeValue.code);
            });
          }
        }
      });
    }
  });
});

editable Boolean

Indicates whether the field is editable.

Default Value:true

length Number

The field length.

Default Value:-1

name String

The name of the field.

Default Value:null

nullable Boolean

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

Default Value:true

type String

The data type of the field.

Possible Values:"small-integer"|"integer"|"single"|"double"|"long"|"string"|"date"|"oid"|"geometry"|"blob"|"raster"|"guid"|"global-id"|"xml"

Default Value:null

valueType String

Since: ArcGIS API 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
name-or-title	Text that represents a name, title, label, or keyword for each feature.
description	Text that provides a longer description of the feature, more than just a name or title.
type-or-category	Types or categories that group features based on common characteristics.
count-or-amount	Integers (no decimal) that represent how many or how much there is of a specific attribute.
percentage-or-ratio	Number values in this field reflect the relationship between different quantities.
measurement	A number that reflects a characteristic that you can precisely measure.
unique-identifier	The values in this field are used to positively distinguish one feature or entity from another.
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.
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.
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.
coordinate	These fields store a geographic coordinate value such as x, y, z, latitude, or longitude.
date-and-time	Values in this field store explicit dates and times or date references such as days of the week, months, or years.
none	No specified type.

Possible Values:"binary"|"coordinate"|"count-or-amount"|"date-and-time"|"description"|"location-or-place-name"|"measurement"|"name-or-title"|"none"|"ordered-or-ranked"|"percentage-or-ratio"|"type-or-category"|"unique-identifier"

See also:

• Blog - Describing layer attributes with field descriptions

• Describe attribute fields - ArcGIS Online Help

Method Overview

Method Details

fromJSON(json){*}static

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

toJSON(){Object}

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

Returns:

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