ElementExpressionInfo

// Creates an ordered list in a cluster's popup
// listing the type of fuel used to generate power in the cluster
// ordered by the total number of power plants for each fuel type.
layer.featureReduction = {
  type: "cluster",
  popupTemplate: {
    title: "Power plant summary",
    content: [{
      type: "expression",
      expressionInfo: {
        expression: `
          // Specify which fields are required by the expression
          Expects($aggregatedFeatures, "fuel1", "capacity_mw")

          // Query stats for each fuel type
          var statsFS = GroupBy($aggregatedFeatures,
            [
              { name: 'Type', expression: 'fuel1'},
            ],
            [  // statistics to return for each unique category
              { name: 'capacity_total', expression: 'capacity_mw', statistic: 'SUM' },
              { name: 'capacity_max', expression: 'capacity_mw', statistic: 'MAX' },
              { name: 'num_features', expression: '1', statistic: 'COUNT' }
            ]
          );
          // create an list in descending order based
          // on the number of plants for each fuel type.
          var ordered = OrderBy(statsFs, 'num_features DESC');

          var list = "<ol>";

          for (var group in ordered){
            list += \`<li>\${group.Type} (\${Text(group.num_features, "#,###")})</li>\`
          }
          list += "</ol>";

          // The return dictionary must return a text, fields, or media
          // popup element as defined in the web map specification
          return {
            type: "text",
            text: list
          }
        `,
        title: "List of fuel types"
      }
    }]
  }
};

Property Overview

Property Details

declaredClass Stringreadonly inherited

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

expression String

The Arcade expression evaluating to a dictionary. The dictionary must represent either a TextContent, FieldsContent, or a MediaContent popup content element as defined in the Popup Element web map specification.

This expression may access data values from the feature, its layer, or other layers in the map or datastore with the $feature, $layer, $map, and $datastore profile variables. See the Popup Element Arcade Profile specification for more information and examples of valid return dictionaries.

See also

• Popup Element web map specification

• Popup Element Profile

• Arcade Profiles: Popup Element Specification

• Sample - Create popup charts from Arcade expressions

• Sample - Popup charts for point clusters

Example

// Creates an column chart where each category/value
// is an aggregate of two or more fields
layer.popupTemplate = {
  title: "Educational Attainment",
  content: [{
    type: "expression",
    expressionInfo: {
      expression: `
        // Create a dictionary of attributes representing the values
        // to display in the table
        var attributes = {
          "No School": $feature.no_school + $feature.some_primary,
          "Primary": $feature.primary_complete + $feature.some_secondary,
          "Secondary": $feature.secondary_complete + $feature.some_highSchool,
          "High School": $feature.highSchool_diploma + $feature.highSchool_ged + $feature.some_college,
          "College/University": $feature.associates + $feature.bachelors + $feature.masters + $feature.doctorate + $feature.professional;
        };

        var fieldInfos = [];

        // Create an array representing the attribute names (or keys)
        // to include in the chart
        for (var k in attributes){
          Push(fieldInfos, {
            fieldName: k
          });
        }

        // Returns a dictionary providing the information
        // required by the popup to render a table of key value pairs
        return {
          type: "media",
          attributes: attributes,
          // The list of attribute names (keys) to include in the table
          fieldInfos: fieldInfos
        };
      `,
      title: "Educational Attainment"
    }
  }]
};

returnType String

The return type of the expression. Content element expressions always return dictionaries.

For ElementExpressionInfo the returnType is always "dictionary".

title String

The title used to describe the popup element returned by the expression.

Method Overview

Method Details

addHandles(handleOrHandles, groupKey)inherited

Since: ArcGIS Maps SDK 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 }
);

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.

clone(){ElementExpressionInfo}

Creates a deep clone of the ElementExpressionInfo instance.

Returns

Type	Description
ElementExpressionInfo	A deep clone of the ElementExpressionInfo instance.

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 Maps SDK 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 Maps SDK 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.