require(["esri/layers/support/ExpressionInfo"], (ExpressionInfo) => { /* code goes here */ });
import ExpressionInfo from "@arcgis/core/layers/support/ExpressionInfo.js";
esri/layers/support/ExpressionInfo
The ExpressionInfo class references an Arcade expression following
the specification defined by the Arcade Visualization Profile.
Expressions must return a string or a number and may access data values from the feature
with the $feature profile variable.
This expression is used for defining an AggregateField for use in a FeatureReductionBinning or a FeatureReductionCluster renderer, popup, or label. It is executed once defined inside a layer's featureReduction property.
const expressionInfo = new ExpressionInfo({
title: "Population per square kilometer",
returnType: "number",
expression: "$feature.population / AreaGeodetic($feature, 'square-kilometers')"
});Constructors
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Parameterproperties Objectoptional
See the properties for a list of all the properties that may be passed into the constructor.
Property Overview
| Name | Type | Summary | Class |
|---|---|---|---|
| String | The name of the class. | Accessor | |
| String | An Arcade expression following the specification defined by the Arcade Visualization Profile. | ExpressionInfo | |
| String | Indicates the return type of the Arcade expression. | ExpressionInfo | |
| String | The title used to describe the value returned by the expression. | ExpressionInfo |
Property Details
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expression
Propertyexpression String -
An Arcade expression following the specification defined by the Arcade Visualization Profile. Expressions must return a string or a number and may access data values from the feature with the
$featureprofile variable.- See also
Example// Calculates the percentage of the population that is Asian expressionInfo.expression = "($feature.Asian / $feature.TOT_POP) * 100";
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returnType
PropertyreturnType String -
Indicates the return type of the Arcade expression.
Possible Values:"string"|"number"
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title
Propertytitle String -
The title used to describe the value returned by the expression.
ExampleexpressionInfo.title = "Percent Asian";
Method Overview
| Name | Return Type | Summary | Class |
|---|---|---|---|
Adds one or more handles which are to be tied to the lifecycle of the object. | Accessor | ||
| this | Creates a deep clone of this object. | ExpressionInfo | |
| * | Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product. | ExpressionInfo | |
| 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. | ExpressionInfo |
Method Details
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Inherited from Accessor
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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();ParametershandleOrHandles WatchHandle|WatchHandle[]Handles marked for removal once the object is destroyed.
groupKey *optionalKey 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.
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Creates a deep clone of this object. Any properties that store values by reference will be assigned copies of the referenced values on the cloned instance.
ReturnsType Description this A deep clone of the class instance that invoked this method.
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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
jsonparameter 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.Parameterjson ObjectA 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.
ReturnsType Description * Returns a new instance of this class.
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hasHandles
InheritedMethodhasHandles(groupKey){Boolean}Inherited from Accessor -
Returns true if a named group of handles exist.
ParametergroupKey *optionalA group key.
ReturnsType Description Boolean Returns trueif 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"); }
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Inherited from Accessor
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Removes a group of handles owned by the object.
ParametergroupKey *optionalA group key or an array or collection of group keys to remove.
Exampleobj.removeHandles(); // removes handles from default group obj.removeHandles("handle-group"); obj.removeHandles("other-handle-group");
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toJSON
MethodtoJSON(){Object} -
Converts an instance of this class to its ArcGIS portal JSON representation. See the Using fromJSON() guide topic for more information.
ReturnsType Description Object The ArcGIS portal JSON representation of an instance of this class.