StreamLayerView

Property Overview

Property Details

connectionError Errorreadonly

The error that explains an unsuccessful attempt to connect to the stream service or an unexpected disconnection from the stream service.

connectionStatus Stringreadonly

The status of the Web Socket connection with the stream service. This property can be watched to see if the connection is lost unexpectedly.

Starting at version 4.26, the connectionStatus can be "paused" if the pause() method is called or if the layer becomes suspended.

Possible Values:"connected"|"disconnected"|"paused"

declaredClass Stringreadonly inherited

Since: ArcGIS Maps SDK for JavaScript 4.7

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

featureEffect FeatureEffectautocast

Since: ArcGIS Maps SDK for JavaScript 4.22

The featureEffect can be used to draw attention features of interest. It 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.

If the featureEffect is set on the layer, it will be inherited by layerView.featureEffect unless the developer overrides it on the layerView. The layerView.featureEffect will take precedence over layer.featureEffect if both properties are set.

Known Limitations

• FeatureEffect is not supported in the following scenarios:
  • In 3D SceneViews
  • In a layer rendered with a HeatmapRenderer
  • When FeatureReductionCluster is enabled
  • When a map is printed
• A FeatureEffect set on a layerView cannot persisted in a WebMap.

See also

• StreamLayer.featureEffect

• Sample - Apply effects to features

• Sample - Apply drop-shadow effect to a layerView

Examples

// gray out features that fall outside of the 3 mile buffer of the mouse's location
// by setting feature effect on excluded features
layerView.featureEffect = new FeatureEffect({
  filter: new FeatureFilter({
    geometry: filterGeometry,
    spatialRelationship: "intersects",
    distance: 3,
    units: "miles"
  }),
  excludedEffect: "grayscale(100%) opacity(30%)"
});

// Apply a drop-shadow feature effect to the features that intersect the borough boundaries,
// while applying blur and brightness effects to the features that are excluded from filter criteria.
// The resulting map will make it easier to spot if the residents are more likely to experience deprivation
// if they live on a borough boundary.
const featureFilter = new FeatureFilter({
  where: "BoroughEdge='true'"
});
layerView.featureEffect = new FeatureEffect({
  filter: featureFilter,
  includedEffect: "drop-shadow(3px, 3px, 3px, black)",
  excludedEffect: "blur(1px) brightness(65%)"
});

filter FeatureFilterautocast

Since: ArcGIS Maps SDK 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

• Sample - Filter features by attributes

• Sample - Filter features by geometry

Example

// display earthquakes that have
// magnitude value of 3 or higher
layerView.filter = new FeatureFilter({
  where: "mag >= 3",
});

highlightOptions HighlightOptions

Since: ArcGIS Maps SDK for JavaScript 4.26

Options for configuring the highlight. Use the highlight() method on the layer view to highlight a feature. The layerView's highlightOptions will take precedence over the view's highlightOptions if both properties are set.

Known Limitations

• The highlightOptions on layer views are only supported in 2D MapView.

See also

• highlight()

• Sample: Highlight SceneLayer

• Sample: Highlight point features

Example

// Features in the layerview will be highlighted with bright
// yellow colors in the map.
const layerView = await view.whenLayerView(layer);
layerView.highlightOptions = {
  color: [255, 255, 0, 1],
  haloOpacity: 0.9,
  fillOpacity: 0.2
};

layer Layerreadonly inherited

The layer being viewed.

spatialReferenceSupported Booleanreadonly inherited

Since: ArcGIS Maps SDK for JavaScript 4.23

Indicates if the spatialReference of the MapView is supported by the layer view. When false layer view will be suspended.

See also

• suspended

suspended Booleanreadonly inherited

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

See also

• spatialReferenceSupported

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. Value of this property is inherited from the layer.visible unless the developer overrides it. The layerView.visible will take precedence over layer.visible if both properties are set.

Default Value:true

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.

createQuery(){Query}

Since: ArcGIS Maps SDK for JavaScript 4.27

Creates a 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 outSpatialReference is set to the spatial reference of the view. Parameters of the filter currently applied to the layer view are also incorporated in the returned query object. The results will include geometries of features and values for all fields.

Returns

Type	Description
Query	The query object

Example

const query = streamLayerView.createQuery();
query.where = "status = 'in progress'";
csvLayerView.queryFeatures(query).then(function(results) {
  console.log(results);
})
.catch(function(error) {
  console.log(error);
});

emit(type, event){Boolean}

Since: ArcGIS Maps SDK for JavaScript 4.5

Emits an event on the instance. This method should only be used when creating subclasses of this class.

Parameters

type String The name of the event.

event Object optional The event payload.

Returns

Type	Description
Boolean	true if a listener was notified

hasEventListener(type){Boolean}

Indicates whether there is an event listener on the instance that matches the provided event name.

Parameter

type String The name of the event.

Returns

Type	Description
Boolean	Returns true if the class supports the input event.

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");
}

highlight(target){Handle}

Highlights the given feature(s) in a layer view. The layerView's highlightOptions will take precedence over the view's highlightOptions if both properties are set.

Release specific changes:

• At version 4.23, the highlight() method was added to ImageryLayerView.

Parameter

target Graphic|Graphic[]|Number|Number[] 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

• highlightOptions

• SceneView.highlightOptions
• MapView.highlightOptions

• Sample: Highlight point features

Examples

// highlight features based on a query result
let highlight;
view.whenLayerView(treesLayer).then(function(layerView){
  layerView.highlightOptions = {
    color: "#FF00FF", //bright fuschia
    haloOpacity: 0.8,
    fillOpacity: 0.3
  };
  let query = treesLayer.createQuery();
  query.where = "type = 'Quercus'";
  treesLayer.queryFeatures(query).then(function(result){
    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.

on(type, listener){Object}

Registers an event handler on the instance. Call this method to hook an event with a listener.

Parameters

type String|String[] An event or an array of events to listen for.

listener Function The function to call when the event fires.

Returns

Type	Description
Object	Returns an event handler with a remove() method that should be called to stop listening for the event(s). Property Type Description remove Function When called, removes the listener from the event.

Example

view.on("click", function(event){
  // event is the event handle returned after the event fires.
  console.log(event.mapPoint);
});

pause()

Since: ArcGIS Maps SDK for JavaScript 4.26

Pauses the connection and stops new observations from being applied until resume() is called. The web socket is open and is still sending data but the layer view will not update. It changes the connectionStatus to paused.

See also

• resume

queryExtent(query, options){Promise<object>}

Since: ArcGIS Maps SDK for JavaScript 4.9

Executes a Query against features available for drawing in the layerView and returns the Extent of features that satisfy the query. If query parameters are not provided, the extent and count of all features available for drawing are returned.

Known Limitations

• Spatial queries have the same limitations as those listed in the projection engine documentation.
• Spatial queries are not currently supported if the layerView 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, spatial, and temporal 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.

Example

let layer = new StreamLayer({
  url: streamLayerUrl  // URL to a stream service
});

view.whenLayerView(layer).then(function(layerView){
  layerView.watch("updating", function(val){
    if(!val){  // wait for the layerView to finish updating
      layerView.queryExtent().then(function(results){
        view.goTo(results.extent);  // go to the extent of all the graphics in the layerView
      });
    }
  });
});

queryFeatureCount(query, options){Promise<number>}

Since: ArcGIS Maps SDK for JavaScript 4.9

Executes a Query against features available for drawing in the layerView 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.

Known Limitations

• Spatial queries have the same limitations as those listed in the projection engine documentation.
• Spatial queries are not currently supported if the layerView 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, spatial, and temporal 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

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){
    reactiveUtils.whenOnce(() => !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
    });
  });
});

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>}

Since: ArcGIS Maps SDK for JavaScript 4.9

Executes a Query against features available for drawing in the layerView and returns a FeatureSet. If query parameters are not provided, all features available for drawing are returned.

Known Limitations

• Spatial queries have the same limitations as those listed in the projection engine documentation.
• Spatial queries are not currently supported if the layerView 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, spatial, and temporal 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<FeatureSet>	When resolved, a FeatureSet containing an array of graphic features is returned.

Examples

view.whenLayerView(layer).then(function(layerView){
  layerView.watch("updating", function(val){
    if(!val){  // wait for the layerView to finish updating
      layerView.queryFeatures(query).then(function(results){
        console.log(results.features);  // prints the array of client-side graphics to the console
      });
    }
  });
});

// returns all the graphics from the layerView
view.whenLayerView(layer).then(function(layerView){
  layerView.watch("updating", function(val){
    if(!val){  // wait for the layerView to finish updating
      layerView.queryFeatures().then(function(results){
        console.log(results.features);  // prints all the client-side graphics to the console
      });
    }
  });
});

queryLatestObservations(query, options){Promise<FeatureSet>}

Since: ArcGIS Maps SDK for JavaScript 4.9

If a trackIdField is specified on the stream service, this method executes a Query against features available for drawing in the layerView and returns a FeatureSet of the latest observations for each trackId that satisfy the query. Otherwise, an Error will be thrown when the method is called.

Known Limitations

• Spatial queries have the same limitations as those listed in the projection engine documentation.
• Spatial queries are not currently supported if the layerView 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, spatial, and temporal 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<FeatureSet>	When resolved, returns the FeatureSet that satisfy the input query.

Example

let layer = new StreamLayer({
  url: streamLayerUrl  // URL to a Stream Service
});

view.whenLayerView(layer).then(function(layerView){
  layerView.watch("updating", function(val){
    if(!val){  // wait for the layerView to finish updating
      layerView.queryLatestObservations().then(function(results){
        console.log(results.features);  // prints all the client-side graphics to the console
      });
    }
  });
});

queryObjectIds(query, options){Promise<number[]>}

Since: ArcGIS Maps SDK for JavaScript 4.9

Executes a Query against features available for drawing in the layerView 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.

Known Limitations

• Spatial queries have the same limitations as those listed in the projection engine documentation.
• Spatial queries are not currently supported if the layerView 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, spatial, and temporal 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

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){
    reactiveUtils.whenOnce(() => !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
    });
  });
});

// returns all the Ids from the graphics in the layerView
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
});

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");

resume()

Since: ArcGIS Maps SDK for JavaScript 4.26

Resumes the connection and the new observations will be applied. The layer view will update to show changes. It changes the connectionStatus to connected if the connection is successful.

See also

• pause

when(callback, errback){Promise}inherited

Since: ArcGIS Maps SDK 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
});

Event Overview

Event Details

data-received

Fires when the layer view receives features. The event payload contains the attributes and geometry of a feature received from the stream service.

Properties

attributes Object Name-value pairs of fields and field values associated with the received data.

geometry Object A location of the received data containing x, y coordinates for points, paths for lines, and rings for polygons, along with the spatial reference wkid.

message-received

Since: ArcGIS Maps SDK for JavaScript 4.26

Fires when the layer view receives a message sent to the websocket connection.

Property

message Object The message object sent to the websocket connection.

update-rate

Since: ArcGIS Maps SDK for JavaScript 4.17

Fires after the layer starts receiving updates from the stream service. It will return the websocket and the client update rates per second. The update rate indicates number of features are being pushed from the server and being processed on the client side. The client update rate will be approximately equal to the websocket update rate unless the service is pushing updates at a rate faster than the client can handle. In which case, the API will down-throttle the update rate and will cause the client update rate to be lower.

Properties

client Number The client update rate per second. Returns number of features being processed on the client.

websocket Number Update rate per second for websocket/service. Returns number of features being pushed from the server.