Property Overview

Property Details

connectionErrorErrorreadonly

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

connectionStatusStringreadonly

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

Possible Values: connected | disconnected

declaredClassStringreadonly inherited

Since: ArcGIS API for JavaScript 4.7

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

filterObjectreadonly

Contains the attribute and spatial filters used to filter messages sent to the given layer view by a stream service. To change the filter for only a single layer view, use the updateFilter() method. The layer view's filter is always updated when the updateFilter() method of the associated stream layer instance is called.

Properties:

geometry Extent optional A spatial filter for filtering features. Only features that intersect the given geometry are displayed in the view.

where String optional A SQL where clause used to filter features by attributes.

See also:

• StreamLayer.filter

graphicsCollection<Graphic>

Contains the collection of graphics visible in the layer view for the live stream. Graphics may be removed from the layer view by calling the removeAll() method from Collection.

Example:

// removes all stream layer graphics from view
// new messages add features to the view
view.whenLayerView(streamLayer)
  .then(function(layerView){
    layer.graphics.removeAll();
  });

layerLayerreadonly inherited

The layer being viewed.

suspendedBooleanreadonly inherited

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

updatingBooleanreadonly inherited

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

Default Value:false

visibleBoolean 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

Method Details

connect(){Promise}

Opens a web socket connection with the stream service to start receiving messages. This is called internally when the StreamLayer is added to a view.

Returns:

Type	Description
Promise	The promise is resolved if the connection is successful or rejected with an error if the connection failed

disconnect()

Closes the web socket connection with the stream service. This is called internally when the StreamLayer is removed from a view.

To verify when the connection is closed, watch the connectionStatus property.

emit(type, event)

Since: ArcGIS API 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 The event payload.

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.

highlight(target){Object}

Highlights the given feature(s).

Known Limitations

Currently the highlight method is only supported in a SceneView.

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
Object	Returns a highlight handler with a remove() method that can be called to remove the highlight. Property Type Description remove Function When called, removes the highlight of the selected graphics.

See also:

• SceneView.highlightOptions

• Sample: Highlight point features

Example:

// highlight feature on pointer-move
view.on("pointer-move", function(event){
  view.hitTest(event).then(function(response){
    if (response.results.length) {
      var graphic = response.results.filter(function (result) {
        return result.graphic.layer === myLayer;
      })[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 The name of event to listen for.

listener Function The function to call when the event is fired.

Returns:

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

See also:

• dojo/on

Example:

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

updateFilter(filter){Promise<Object>}

Updates the filter on the StreamLayerView. The filter is updated only on the layer view from which it is called. To update the filter on all layer views generated from a common layer, use the StreamLayer.updateFilter() method. If the input filter object is undefined or null, the spatial and attribute filters are removed.

Filter changes only apply to incoming features. Features already displayed in the view are not filtered. Therefore, you may want to clear the graphics in the layer view prior to applying a new filter. To do so, get the layer view then call removeAll() on the StreamLayerView.graphics. You may also filter features already present in the view using the Collection methods. See the examples below.

Parameters:

filter Object Updates the spatial and attribute filters. If null, all filters are cleared. Specification: geometry Extent optional A spatial filter for filtering features. Only features that intersect the given geometry are displayed in the view. If null, the spatial filter is cleared. where String optional A SQL where clause used to filter features by attributes. If null, the attribute filter is cleared.

Returns:

Type	Description
Promise<Object>	Resolves to an object that has a filter property, indicating the filter set on the stream service by the layer view. If the filter could not be updated, the promise is rejected with an error that explains why the filter failed to update.

See also:

• StreamLayer.updateFilter()

Examples:

view.whenLayerView(layer)
 .then(function(layerView){
   layerView.graphics.removeAll();

   // updates the spatial filter based on the current view's extent
   // and removes the attribute filter
   layerView.updateFilter({
     geometry: view.extent.filter(),
     where: null
   });
 });

// updates the attribute filter to only display features whose
// route ID is 110
layerView.updateFilter({
  where: "ROUTE_ID = 110"
});

// clears all filters from the layer
layerView.updateFilter(null);

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 then() in the same way
var 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 data. The event object contains the message properties received from the stream service.