Method Overview

Method Details

getDisplayFieldName(fields){String}

Since: ArcGIS API for JavaScript 4.15

Gets the appropriate display field name to label a feature.

Parameter:

fields Field[] An array of fields to determine the display field from.

Returns:

Type	Description
String	The name of the display field to use for labeling.

getElevationFields(layer){Promise<string[]>}

Returns an array of field names used in the Arcade expression for calculating the z-values of features in the given feature layer's FeatureLayer.elevationInfo.

Parameter:

layer FeatureLayer The featureLayer to extract fields required for calculating feature z-values.

Returns:

Type	Description
Promise<string[]>	When resolved, returns an array of field names.

getExpressionFields(layer, expressions){Promise<string[]>}

Since: ArcGIS API for JavaScript 4.15

Returns an array of field names referenced in one or more Arcade expressions to be set on the given layer in either the renderer, labelingInfo, or popupTemplate. This is useful for when you want to request the data for these fields prior to updating a renderer for fast visual updates or when you want to execute a client-side query on that data prior to setting the Arcade expressions on the layer.

Parameters:

layer FeatureLayer|CSVLayer|GeoJSONLayer|SceneLayer|StreamLayer The layer for which the Arcade expressions are authored. This layer must have a fields property.

expressions String[] An array of Arcade expressions to be set on the given layer.

Returns:

Type	Description
Promise<string[]>	Returns an array of field names declared either by the $feature.fieldName or $feature[fieldName] syntax.

See also:

• Arcade - expression language

Example:

const windDirectionExpression = `
  $feature["WIND_DIRECT"];
  $feature["WIND_SPEED"];
  var DEG = $feature.WIND_DIRECT;
  var SPEED = $feature.WIND_SPEED;
  var DIR = When( SPEED == 0, "",
    (DEG < 22.5 && DEG >= 0) || DEG > 337.5, "N",
    DEG >= 22.5 && DEG < 67.5, "NE",
    DEG >= 67.5 && DEG < 112.5, "E",
    DEG >= 112.5 && DEG < 157.5, "SE",
    DEG >= 157.5 && DEG < 202.5, "S",
    DEG >= 202.5 && DEG < 247.5, "SW",
    DEG >= 247.5 && DEG < 292.5, "W",
    DEG >= 292.5 && DEG < 337.5, "NW", "" );
  return SPEED + " mph " + DIR;
`;

const labelExpressions = [
  "Round($feature.TEMP) + '° F';",
  "$feature.R_HUMIDITY + '% RH'",
  "$feature.STATION_NAME",
  windDirectionExpression
];

// Assume the layer has only requested the OBJECTID field
fieldUtils.getExpressionFields(layer, labelExpressions)
 .then(function(fieldNames){

  // fieldNames = ["R_HUMIDITY", "STATION_NAME", "TEMP", "WIND_DIRECT", "WIND_SPEED"]
  layer.outFields = fieldNames;

  // Do something else like a client-side query with those fields
 }).catch(function(error){
   console.error(error);
 });

getFeatureEditFields(layer){String[]}

Returns an array of editor tracking field names for a given feature layer. It includes the fields from the FeatureLayer.editFieldsInfo.

Parameter:

layer FeatureLayer The Feature Layer from which to extract editor tracking fields.

Returns:

Type	Description
String[]	An array of field names used for editor tracking.

getLabelingFields(layer){Promise<string[]>}

Returns an array of field names used in the Arcade expression for labeling features in the given feature layer's FeatureLayer.labelingInfo.

Parameter:

layer FeatureLayer The Feature Layer from which to extract label fields.

Returns:

Type	Description
Promise<string[]>	When resolved, returns an array of field names used for labeling.

getTimeFields(layer){Promise<string[]>}

Returns an array of field names related to time. It includes the fields from the FeatureLayer.timeInfo, and the trackIdField.

Parameter:

layer FeatureLayer The Feature Layer from which to extract time fields.

Returns:

Type	Description
Promise<string[]>	When resolved, returns an array of time field names.