AggregateField

AMD: require(["esri/layers/support/AggregateField"], (AggregateField) => { /* code goes here */ });
ESM: import AggregateField from "@arcgis/core/layers/support/AggregateField";
Class: esri/layers/support/AggregateField
Inheritance: AggregateField Accessor
Since: ArcGIS API for JavaScript 4.24

Defines the aggregate fields used in a layer visualized with FeatureReductionBinning or FeatureReductionCluster. An aggregate field aggregates data from a layer's field using a statistic type such as the average or sum.

See also
Example
featureReduction.fields = [{
  name: "SUM_population",
  alias: "Total population",
  onStatisticField: "population",
  statisticType: "sum"
}, {
  name: "AVG_age",
  alias: "Average age",
  onStatisticField: "age",
  statisticType: "avg"
}];

Constructors

new AggregateField(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 Working with Properties topic.
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Name Type Summary Class
String

The display name that describes the aggregate field in the Legend, Popup, and other UI elements.

more details
AggregateField
String

The name of the class.

more details
Accessor
Boolean

Indicates whether the field was created internally by the JS API's rendering engine for default FeatureReductionCluster visualizations.

more details
AggregateField
String

The name of the aggregate field.

more details
AggregateField
ExpressionInfo

An object containing an Arcade expression, which evaluates for each child feature represented by the aggregate graphic.

more details
AggregateField
String

The name of the layer field to summarize with the given statisticType.

more details
AggregateField
String

Defines the type of statistic used to aggregate data returned from onStatisticField or onStatisticExpression.

more details
AggregateField

Property Details

alias String

The display name that describes the aggregate field in the Legend, Popup, and other UI elements.

Default Value:null
Example
aggregateField.alias = "Total population";
declaredClass Stringreadonly inherited

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

isAutoGenerated Boolean
Since: ArcGIS API for JavaScript 4.25

Indicates whether the field was created internally by the JS API's rendering engine for default FeatureReductionCluster visualizations. You should avoid setting or changing this value. If true, then all other properties of the AggregateField are read-only.

Default Value:false
name String

The name of the aggregate field. This should describe the layer's field and aggregation method used. For example, if creating a field that contains the total population for a set of features with a population field, then you could name this field total_population or popuplation_sum.

This field name must start with a letter, and may only contain alphanumeric characters and underscore.

Example
// names the aggregate field that will display the sum of the population
// for all points representing cities in the bin
aggregateField.name = "SUM_population";
onStatisticExpression ExpressionInfo
Since: ArcGIS API for JavaScript 4.25

An object containing an Arcade expression, which evaluates for each child feature represented by the aggregate graphic. All results of the expression will be aggregated using the given statisticType. This expression must follow the specification defined by the Arcade Visualization Profile. Expressions must return a string or a number and may access data values from the layer's feature with the $feature profile variable.

Example
// will create an aggregate field for the Population field of the layer.
aggregateField.onStatisticExpression = new ExpressionInfo({
  title: "Population per square kilometer",
  returnType: "number",
  expression: "$feature.population / AreaGeodetic($feature, 'square-kilometers')"
});
onStatisticField String
Since: ArcGIS API for JavaScript 4.25

The name of the layer field to summarize with the given statisticType.

Example
// will create an aggregate field for the Population field of the layer.
aggregateField.onStatisticField = "Population";
statisticType String
Since: ArcGIS API for JavaScript 4.25

Defines the type of statistic used to aggregate data returned from onStatisticField or onStatisticExpression.

Possible Values

Value Description
avg The average of values in the aggregate. Only available for fields and expressions that return numbers.
count The total number of features in the aggregate. A field does not need to be specified in this case.
max The maximum of all values in the aggregate. Only available for fields and expressions that return numbers.
min The minimum of all values in the aggregate. Only available for fields and expressions that return numbers.
mode The most common or predominant value in the aggregate. Available for fields and expressions that return numbers or strings.
sum The sum of all values in the aggregate. Only available for fields and expressions that return numbers.

Possible Values:"avg"|"count"|"max"|"min"|"mode"|"sum"

Example
// will calculate the sum of the field specified in onStatisticField for all features in the bin.
outStatistic.statisticType = "sum";

Method Overview

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Name Return Type Summary Class

Adds one or more handles which are to be tied to the lifecycle of the object.

more details
Accessor
AggregateField

Creates a deep clone of the AggregateField object.

more details
AggregateField
*

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

more details
AggregateField
Boolean

Returns true if a named group of handles exist.

more details
Accessor

Removes a group of handles owned by the object.

more details
Accessor
Object

Converts an instance of this class to its ArcGIS portal JSON representation.

more details
AggregateField

Method Details

addHandles(handleOrHandles, groupKey)inherited
Since: ArcGIS API for JavaScript 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 }
);

// Handle gets removed when the object is destroyed.
this.addHandles(handle);
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(){AggregateField}

Creates a deep clone of the AggregateField object.

Returns
Type Description
AggregateField A deep clone of the object that invoked this method.
Example
// Creates a deep clone of the AggregateField object
const sumPopulationField = layer.featureReduction.fields.find( field => field.name === "SUM_population" ).clone();
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(groupKey){Boolean}inherited
Since: ArcGIS API for JavaScript 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(groupKey)inherited
Since: ArcGIS API for JavaScript 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(){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.

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