FeatureLayerView

Class: esri/views/layers/FeatureLayerView
Inheritance: FeatureLayerView LayerView Accessor
Since: ArcGIS API for JavaScript 4.0

Represents the LayerView of a FeatureLayer after it has been added to a Map in either a MapView or SceneView.

The FeatureLayerView is responsible for rendering a FeatureLayer's features as graphics in the View. The methods in the FeatureLayerView provide developers with the ability to query and highlight graphics in the view. See the code snippets in the methods below for examples of how to access client-side graphics from the view.

See also:

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.
Show inherited properties Hide inherited properties
Name Type Summary Class
String[]more details

A list of attribute fields fetched for each feature including fields required for layer rendering, labeling, elevation info, and additional fields defined on the FeatureLayer.outFields.

more detailsFeatureLayerView
Stringmore details

The name of the class.

more detailsAccessor
FeatureEffectmore details

The effect applied to the layer view.

more detailsFeatureLayerView
FeatureFiltermore details

The attribute, geometry, and time extent filter.

more detailsFeatureLayerView
FeatureLayermore details

The layer being viewed.

more detailsFeatureLayerView
Numbermore details

The maximum number of features that can be displayed at a time.

more detailsFeatureLayerView
Booleanmore details

Signifies whether the maximum number of features has been exceeded.

more detailsFeatureLayerView
Booleanmore details

Value is true if the layer is suspended (i.e., layer will not redraw or update itself when the extent changes).

more detailsLayerView
Booleanmore details

Value is true when the layer is updating; for example, if it is in the process of fetching data.

more detailsLayerView
Booleanmore details

When true, the layer is visible in the view.

more detailsLayerView

Property Details

availableFields String[]readonly
Since: ArcGIS API for JavaScript 4.11

A list of attribute fields fetched for each feature including fields required for layer rendering, labeling, elevation info, and additional fields defined on the FeatureLayer.outFields. The availableFields property is populated when the layer view has finished updating. The availableFields is used when filtering or querying features on the client-side.

See also:
Example:
view.whenLayerView(layer).then(function(layerView){
  layerView.watch("updating", function(value){
    // availableFields will become available
    // once the layer view finishes updating
    if (!value) {
       layerView.queryFeatures({
         outFields: layerView.availableFields,
         where: "DEW_POINT > 10"
       })
       .then(function(results) {
         console.log(results.features.length, " features returned");
       })
       .catch(function(error) {
         console.log("query failed: ", error);
       });
     }
  });
});
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.

Since: ArcGIS API for JavaScript 4.11

The effect applied to the layer view. The effect allows for the selection of features via a filter, and an includedEffect and excludedEffect are applied to those features that respectively pass or fail the filter requirements.

Known Limitations

FeatureEffect is not supported in 3D SceneViews.

See also:
Example:
// set effect on excluded features
// make them gray and transparent
featureLayerView.effect = {
  filter: { // autocasts to FeatureFilter
    geometry: filterGeometry,
    spatialRelationship: geometryRel,
    distance: 3,
    units: "miles"
  },
  excludedEffect: "grayscale(100%) opacity(30%)"
}
Since: ArcGIS API for JavaScript 4.11

The attribute, geometry, and time extent filter. Only the features that satisfy the filter are displayed on the view.

See also:
Example:
// display rain gauges where their water percent is over 30%
// and if the gauges are completely contained by the 10-mile
// buffer around the filter geometry
featureLayerView.filter = new FeatureFilter({
  where: "percentile >= 30",
  geometry: filterPolygon,
  spatialRelationship: "contains",
  distance: 10,
  units: "miles"
});
layer FeatureLayerreadonly

The layer being viewed.

maximumNumberOfFeatures Number
Since: ArcGIS API for JavaScript 4.10

The maximum number of features that can be displayed at a time. This setting currently only applies to SceneView. By default, the maximum number of features is estimated automatically depending on the symbology, geometry complexity, memory consumption and display quality profile.

Changing this setting to a higher value may lead to a significant decrease in performance and increase in memory usage.

maximumNumberOfFeaturesExceeded Boolean
Since: ArcGIS API for JavaScript 4.10

Signifies whether the maximum number of features has been exceeded. Not all features could be displayed when this value is true. This setting currently only applies to SceneView.

suspended Booleanreadonly inherited

Value is true if the layer is suspended (i.e., layer will not redraw or update itself when the extent changes).

updating Booleanreadonly inherited

Value is true when the layer is updating; for example, if it is in the process of fetching data.

Default Value:false
visible Boolean inherited

When true, the layer is visible in the view. Set this property to false to hide the layer from the view.

Default Value:true

Method Overview

Show inherited methods Hide inherited methods
Name Return Type Summary Class
Querymore details

Creates query parameter object that can be used to fetch features as they are being displayed.

more detailsFeatureLayerView
Handlemore details

Highlights the given feature(s).

more detailsFeatureLayerView
Booleanmore details

isFulfilled() may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected).

more detailsLayerView
Booleanmore details

isRejected() may be used to verify if creating an instance of the class is rejected.

more detailsLayerView
Booleanmore details

isResolved() may be used to verify if creating an instance of the class is resolved.

more detailsLayerView
Promise<Object>more details

Executes a Query against features available for drawing in the layer view and returns the Extent of features that satisfy the query.

more detailsFeatureLayerView
Promise<Number>more details

Executes a Query against features available for drawing in the layer view and returns the number of features that satisfy the query.

more detailsFeatureLayerView
Promise<FeatureSet>more details

Executes a Query against features available for drawing in the layer view and returns a FeatureSet.

more detailsFeatureLayerView
Promise<Number[]>more details

Executes a Query against features available for drawing in the layer view and returns array of the ObjectIDs of features that satisfy the input query.

more detailsFeatureLayerView
Promisemore details

when() may be leveraged once an instance of the class is created.

more detailsLayerView

Method Details

createQuery(){Query}
Since: ArcGIS API for JavaScript 4.12

Creates query parameter object that can be used to fetch features as they are being displayed. It sets the query parameter's outFields property to ["*"] and returnGeometry to true. The output spatial reference outSpatialReference is set to the spatial reference of the view. Parameters of the filter currently applied to the layerview are also incorporated in the returned query object. The results will include geometries of features and values for availableFields.

Returns:
Type Description
Query The query parameter object.
highlight(target){Handle}
Since: ArcGIS API for JavaScript 4.4

Highlights the given feature(s).

Parameter:
optional

The feature(s) to highlight. When passing a graphic or array of graphics, each feature must have a valid objectID. You may alternatively pass one or more objectIDs as a single number or an array.

Returns:
Type Description
Handle Returns a highlight handler with a remove() method that can be called to remove the highlight.
See also:
Examples:
// highlight features based on a query result
let highlight;
view.whenLayerView(treesLayer).then(function(layerView){
 let query = treesLayer.createQuery();
 query.where = "type = 'Quercus'";
 treesLayer.queryFeatures(query).then(function(result){
   if (highlight) {
     highlight.remove();
   }
   highlight = layerView.highlight(result.features);
 })
});
// highlight feature on pointer-move
view.on("pointer-move", function(event){
  view.hitTest(event).then(function(response){
    if (response.results.length) {
      let graphic = response.results.filter(function (result) {
        return result.graphic.layer === treesLayer;
      })[0].graphic;

     view.whenLayerView(graphic.layer).then(function(layerView){
       layerView.highlight(graphic);
     });
    }
  });
});
isFulfilled(){Boolean}inherited

isFulfilled() may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected). If it is fulfilled, true will be returned.

Returns:
Type Description
Boolean Indicates whether creating an instance of the class has been fulfilled (either resolved or rejected).
isRejected(){Boolean}inherited

isRejected() may be used to verify if creating an instance of the class is rejected. If it is rejected, true will be returned.

Returns:
Type Description
Boolean Indicates whether creating an instance of the class has been rejected.
isResolved(){Boolean}inherited

isResolved() may be used to verify if creating an instance of the class is resolved. If it is resolved, true will be returned.

Returns:
Type Description
Boolean Indicates whether creating an instance of the class has been resolved.
queryExtent(query, options){Promise<Object>}

Executes a Query against features available for drawing in the layer view and returns the Extent of features that satisfy the query. Valid only for hosted feature services on arcgis.com and for ArcGIS Server 10.3.1 and later. If query parameters are not provided, the extent and count of all features available for drawing are returned.

To query for the extent of features directly from a Feature Service rather than those visible in the view, you must use the FeatureLayer.queryExtent() method.

Known Limitations

  • Spatial queries are executed against quantized geometries in the layer view. The resolution of layer view geometries, is only as precise as the scale resolution of the view. Therefore, the results of the same query could be different when executed at different scales. This also means that geometries returned from any layer view query will likewise be at the same scale resolution of the view.
  • Spatial queries have the same limitations as those listed in the projection engine documentation.
  • Spatial queries are not currently supported if the FeatureLayerView has any of the following SpatialReferences:
    • GDM 2000 (4742) – Malaysia
    • Gusterberg (Ferro) (8042) – Austria/Czech Republic
    • ISN2016 (8086) - Iceland
    • SVY21 (4757) - Singapore
Parameters:
query Query autocast
optional
Autocasts from Object

Specifies the attributes and spatial filter of the query. When no parameters are passed to this method, all features in the client are returned. To only return features visible in the view, set the geometry parameter in the query object to the view's extent.

options Object
optional

An object with the following properties.

Specification:
signal AbortSignal
optional

Signal object that can be used to abort the asynchronous task. The returned promise will be rejected with an Error named AbortError when an abort is signaled. See also AbortController for more information on how to construct a controller that can be used to deliver abort signals.

Returns:
Type Description
Promise<Object> When resolved, returns the extent and count of the features that satisfy the input query. See the object specification table below for details.
Property Type Description
count Number The number of features that satisfy the input query.
extent Extent The extent of the features that satisfy the query.
Examples:
let layer = new FeatureLayer({
  url: fsUrl  // points to a Feature Service layer url
});

view.whenLayerView(layer).then(function(layerView){
  layerView.watch("updating", function(val){
    if(!val){  // wait for the layer view to finish updating
      layerView.queryExtent().then(function(results){
        view.goTo(results.extent);  // go to the extent of all the graphics in the layer view
      });
    }
  });
});
// Expand the extent so that a feature (i.e. point feature)
// won't be off screen after the end of goTo animation.
layerView.queryExtent()
 .then(function(result) {
   const zoomScale = 16000;
   const extent = result.extent;

   extent.expand((zoomScale / view.scale) * view.resolution);
   view.goTo(extent);
});
queryFeatureCount(query, options){Promise<Number>}

Executes a Query against features available for drawing in the layer view and returns the number of features that satisfy the query. If query parameters are not provided, the count of all features available for drawing is returned.

To query for the count of features directly from a Feature Service rather than those visible in the view, you must use the FeatureLayer.queryFeatureCount() method.

Known Limitations

  • Spatial queries are executed against quantized geometries in the layer view. The resolution of layer view geometries, is only as precise as the scale resolution of the view. Therefore, the results of the same query could be different when executed at different scales. This also means that geometries returned from any layer view query will likewise be at the same scale resolution of the view.
  • Spatial queries have the same limitations as those listed in the projection engine documentation.
  • Spatial queries are not currently supported if the FeatureLayerView has any of the following SpatialReferences:
    • GDM 2000 (4742) – Malaysia
    • Gusterberg (Ferro) (8042) – Austria/Czech Republic
    • ISN2016 (8086) - Iceland
    • SVY21 (4757) - Singapore
Parameters:
query Query autocast
optional
Autocasts from Object

Specifies the attributes and spatial filter of the query. When no parameters are passed to this method, all features in the client are returned. To only return features visible in the view, set the geometry parameter in the query object to the view's extent.

options Object
optional

An object with the following properties.

Specification:
signal AbortSignal
optional

Signal object that can be used to abort the asynchronous task. The returned promise will be rejected with an Error named AbortError when an abort is signaled. See also AbortController for more information on how to construct a controller that can be used to deliver abort signals.

Returns:
Type Description
Promise<Number> When resolved, returns the number of features satisfying the query.
Examples:
let layer = new FeatureLayer({
  url: fsUrl  // points to a Feature Service layer url
});

view.on("click", function(event){

  let query = new Query();
  query.geometry = event.mapPoint;  // obtained from a view click event
  query.spatialRelationship = "intersects";

  view.whenLayerView(layer).then(function(layerView){
    watchUtils.whenNotOnce(layerView, "updating")
    .then(function(){
      return layerView.queryFeatureCount(query);
    })
    .then(function(count){
      console.log(count);  // prints the number of the client-side graphics that satisfy the query
    });
  });
});
let layer = new FeatureLayer({
  url: fsUrl  // points to a Feature Service layer url
});

view.whenLayerView(layer).then(function(layerView){
  return layerView.queryFeatureCount()
}).then(function(count){
  console.log(count);  // prints the total number of client-side graphics to the console
});
queryFeatures(query, options){Promise<FeatureSet>}

Executes a Query against features available for drawing in the layer view and returns a FeatureSet. If query parameters are not provided, all features available for drawing are returned along with their attributes that are available on the client. For client-side attribute queries, relevant fields should exist in availableFields list for the query to be successful.

To execute a query against all the features in a feature service rather than only those in the client, you must use the FeatureLayer.queryFeatures() method.

Known Limitations

  • Attribute values used in attribute queries executed against layer views are case sensitive.
  • Spatial queries are executed against quantized geometries in the layer view. The resolution of layer view geometries, is only as precise as the scale resolution of the view. Therefore, the results of the same query could be different when executed at different scales. This also means that geometries returned from any layer view query will likewise be at the same scale resolution of the view.
  • Spatial queries have the same limitations as those listed in the projection engine documentation.
  • Spatial queries are not currently supported if the FeatureLayerView has any of the following SpatialReferences:
    • GDM 2000 (4742) – Malaysia
    • Gsterberg (Ferro) (8042) – Austria/Czech Republic
    • ISN2016 (8086) - Iceland
    • SVY21 (4757) - Singapore
Parameters:
query Query autocast
optional
Autocasts from Object

Specifies the attributes and spatial filter of the query. When this parameter is not passed to queryFeatures() method, all features available for drawing are returned along with their attributes that are available on the client. To only return features visible in the view, set the geometry parameter in the query object to the view's extent.

options Object
optional

An object with the following properties.

Specification:
signal AbortSignal
optional

Signal object that can be used to abort the asynchronous task. The returned promise will be rejected with an Error named AbortError when an abort is signaled. See also AbortController for more information on how to construct a controller that can be used to deliver abort signals.

Returns:
Type Description
Promise<FeatureSet> When resolved, a FeatureSet containing an array of graphic features is returned.
See also:
Examples:
let layer = new FeatureLayer({
  url: fsUrl  // points to a Feature Service layer url
});

let query = new Query();
query.geometry = new Extent({
 xmin: -9177811,
 ymin: 4247000,
 xmax: -9176791,
 ymax: 4247784,
 spatialReference: 102100
});
query.spatialRelationship = "intersects";

view.whenLayerView(layer).then(function(layerView){
  layerView.watch("updating", function(val){
    if(!val){  // wait for the layer view to finish updating
      layerView.queryFeatures(query).then(function(results){
        console.log(results.features);  // prints the array of client-side graphics to the console
      });
    }
  });
});
let layer = new FeatureLayer({
  url: fsUrl  // points to a Feature Service layer url
});

// returns all the graphics from the layer view
view.whenLayerView(layer).then(function(layerView){
  layerView.watch("updating", function(val){
    if(!val){  // wait for the layer view to finish updating
      layerView.queryFeatures().then(function(results){
        console.log(results.features);  // prints all the client-side graphics to the console
      });
    }
  });
});
layerView.queryFeatures({
  geometry: mapPoint,
  // 6 pixels around a point at the view resolution to query around a finger.
  distance: view.resolution * 6,
});
queryObjectIds(query, options){Promise<Number[]>}

Executes a Query against features available for drawing in the layer view and returns array of the ObjectIDs of features that satisfy the input query. If query parameters are not provided, the ObjectIDs of all features available for drawing are returned.

To query for ObjectIDs of features directly from a Feature Service rather than those visible in the view, you must use the FeatureLayer.queryObjectIds() method.

Known Limitations

  • Spatial queries are executed against quantized geometries in the layer view. The resolution of layer view geometries, is only as precise as the scale resolution of the view. Therefore, the results of the same query could be different when executed at different scales. This also means that geometries returned from any layer view query will likewise be at the same scale resolution of the view.
  • Spatial queries have the same limitations as those listed in the projection engine documentation.
  • Spatial queries are not currently supported if the FeatureLayerView has any of the following SpatialReferences:
    • GDM 2000 (4742) – Malaysia
    • Gusterberg (Ferro) (8042) – Austria/Czech Republic
    • ISN2016 (8086) - Iceland
    • SVY21 (4757) - Singapore
Parameters:
query Query autocast
optional
Autocasts from Object

Specifies the attributes and spatial filter of the query. When no parameters are passed to this method, all features in the client are returned. To only return features visible in the view, set the geometry parameter in the query object to the view's extent.

options Object
optional

An object with the following properties.

Specification:
signal AbortSignal
optional

Signal object that can be used to abort the asynchronous task. The returned promise will be rejected with an Error named AbortError when an abort is signaled. See also AbortController for more information on how to construct a controller that can be used to deliver abort signals.

Returns:
Type Description
Promise<Number[]> When resolved, returns an array of numbers representing the ObjectIDs of the features satisfying the query.
Examples:
let layer = new FeatureLayer({
  url: fsUrl  // points to a Feature Service layer url
});

view.on("click", function(event){

  let query = new Query();
  query.geometry = event.mapPoint;  // obtained from a view click event
  query.spatialRelationship = "intersects";

  view.whenLayerView(layer).then(function(layerView){
    watchUtils.whenNotOnce(layerView, "updating")
    .then(function(){
      return layerView.queryObjectIds(query);
    })
    .then(function(ids){
      console.log(ids);  // prints the ids of the client-side graphics to the console
    });
  });
});
let layer = new FeatureLayer({
  url: fsUrl  // points to a Feature Service layer url
});

// returns all the Ids from the graphics in the layer view
view.whenLayerView(layer).then(function(layerView){
  return layerView.queryObjectIds()
}).then(function(ids){
  console.log(ids);  // prints the ids of all the client-side graphics to the console
});
when(callback, errback){Promise}inherited
Since: ArcGIS API for JavaScript 4.6

when() may be leveraged once an instance of the class is created. This method takes two input parameters: a callback function and an errback function. The callback executes when the instance of the class loads. The errback executes if the instance of the class fails to load.

Parameters:
callback Function
optional

The function to call when the promise resolves.

errback Function
optional

The function to execute when the promise fails.

Returns:
Type Description
Promise Returns a new promise for the result of callback that may be used to chain additional functions.
Example:
// Although this example uses MapView, any class instance that is a promise may use when() in the same way
let view = new MapView();
view.when(function(){
  // This function will execute once the promise is resolved
}, function(error){
  // This function will execute if the promise is rejected due to an error
});

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