require(["esri/layers/StreamLayer"], function(StreamLayer) { /* code goes here */ });
Class: esri/layers/StreamLayer
Inheritance: StreamLayer FeatureLayer Layer Accessor
Since: ArcGIS API for JavaScript 4.0

The stream layer extends the feature layer to add the ability to connect to a stream of data using HTML5 WebSockets. It connects to a server that emits geographic features continuously. While the feature layer is used to map relatively static data, the stream layer is suitable when you would like to map dynamic streams of data that are unbounded and continuous. When a stream layer is added to a map, users are able to see real-time updates pushed out by the server.

A real-time-enabled data server is required to use this class. The ArcGIS Geoevent Extension for Server is a tool you may use to set up and configure your data stream. In addition, version 10.3 (and above) of ArcGIS GeoEvent Extension for Server exposes stream services. To learn more about this, please see the Stream Services documentation.

The number of features coming from a real-time feed can overload the browser and make the browser unresponsive. Use the purgeOptions construction option to define rules that specify how to remove data when new messages are received and the layer is refreshed.

WebSockets are a feature of HTML5. Most browsers are supporting WebSockets in recent versions. However, they are not supported by all versions of all browsers. To get more information about WebSockets and to test if a browser supports WebSockets, visit WebSocket.org.

See also:

Constructors

new StreamLayer(properties)
Parameter:
properties Object
optional

See the properties for a list of all the properties that may be passed into the constructor.

Example:
var streamLayer = new StreamLayer({
  url: "https://geoeventsample3.esri.com:6080/arcgis/rest/services/SeattleBus/StreamServer",
  purgeOptions: {
    displayCount: 1000
  }
});

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.
NameTypeSummaryClass
Object

Describes the layer's supported capabilities.

more details
more detailsFeatureLayer
String

The name of the class.

more details
more detailsAccessor
String

The SQL where clause used to filter features on the client.

more details
more detailsStreamLayer
Object

Specifies how features are placed on the vertical axis (z).

more details
more detailsFeatureLayer
FeatureReductionSelection

Configures the method for reducing the number of point features in the view.

more details
more detailsStreamLayer
FieldsIndex

A convenient property that can be used to make case-insensitive lookups for a field by name.

more details
more detailsFeatureLayer
Extent

An extent object used to filter features.

more details
more detailsStreamLayer
String

The geometry type of features in the layer.

more details
more detailsStreamLayer
String

The unique ID assigned to the layer.

more details
more detailsLayer
LabelClass[]

The label definition for this layer, specified as an array of LabelClass.

more details
more detailsStreamLayer
Boolean

Indicates whether to display labels for this layer.

more details
more detailsStreamLayer
Boolean

Indicates whether the layer will be included in the legend.

more details
more detailsFeatureLayer
String

Indicates how the layer should display in the LayerList widget.

more details
more detailsLayer
Boolean

Indicates whether the layer's resources have loaded.

more details
more detailsLayer
Error

The Error object returned if an error occurred while loading.

more details
more detailsLayer
String

Represents the status of a load operation.

more details
more detailsLayer
Object[]

A list of warnings which occurred while loading.

more details
more detailsLayer
Number

Maximum number of features to show per trackId.

more details
more detailsStreamLayer
Number

The maximum scale (most zoomed in) at which the layer is visible in the view.

more details
more detailsFeatureLayer
Number

The minimum scale (most zoomed out) at which the layer is visible in the view.

more details
more detailsFeatureLayer
String

The name of an oidfield containing a unique value or identifier for each feature in the layer.

more details
more detailsStreamLayer
Number

The opacity of the layer.

more details
more detailsLayer
Boolean

Indicates whether to display popups when features in the layer are clicked.

more details
more detailsFeatureLayer
PopupTemplate

The popup template for the layer.

more details
more detailsFeatureLayer
Object

Options for purging stale features.

more details
more detailsStreamLayer
Renderer

The renderer assigned to the layer.

more details
more detailsFeatureLayer
Boolean

Apply perspective scaling to screen-size point symbols in a SceneView.

more details
more detailsFeatureLayer
Object

The stream service's metadata JSON exposed by the ArcGIS REST API.

more details
more detailsStreamLayer
SpatialReference

The spatial reference of the layer.

more details
more detailsFeatureLayer
TimeExtent

The layer's time extent.

more details
more detailsFeatureLayer
TimeInfo

TimeInfo provides information such as date fields that store start and end time for each feature and the fullTimeExtent for the layer.

more details
more detailsFeatureLayer
TimeInterval

A temporary offset of the time data based on a certain TimeInterval.

more details
more detailsFeatureLayer
String

The title of the layer used to identify it in places such as the Legend and LayerList widgets.

more details
more detailsFeatureLayer
StringFor StreamLayer the type is always "stream". more detailsmore detailsStreamLayer
String

The URL of the stream service.

more details
more detailsStreamLayer
Boolean

Determines if the layer will update its temporal data based on the view's current timeExtent.

more details
more detailsFeatureLayer
Number

The version of ArcGIS Server in which the layer is published.

more details
more detailsFeatureLayer
Boolean

Indicates if the layer is visible in the View.

more details
more detailsLayer

Property Details

capabilities Objectreadonly inherited

Describes the layer's supported capabilities.

Properties:
attachment Object

Describes what attachment capabilities are enabled on the layer.

Specification:
supportsName Boolean

Indicates if the attachments can be queried by their names.

supportsSize Boolean

Indicates if the attachments can be queried by their sizes.

supportsContentType Boolean

Indicates if the attachments can be queried by their content types.

supportsKeywords Boolean

Indicates if the attachments can be queried by their keywords.

supportsExifInfo Boolean

Indicates if the attachment queries support exifInfo.

data Object

Describes characteristics of the data in the layer.

Specification:
isVersioned Boolean

Indicates if the feature service is versioned.

supportsAttachment Boolean

Indicates if the attachment is enabled on the layer.

supportsM Boolean

Indicates if the features in the layer support M values. Requires ArcGIS Server service 10.1 or greater.

supportsZ Boolean

Indicates if the features in the layer support Z values. Requires ArcGIS Server service 10.1 or greater. See elevationInfo for details regarding placement and rendering of features with z-values in 3D SceneViews.

editing Object

Describes editing capabilities that can be performed on the features in the layer via applyEdits().

Specification:
supportsDeleteByAnonymous Boolean

Indicates if anonymous users can delete features created by others.

supportsDeleteByOthers Boolean

Indicates if logged in users can delete features created by others.

supportsGeometryUpdate Boolean

Indicates if the geometry of the features in the layer can be edited.

supportsGlobalId Boolean

Indicates if the globalId values provided by the client are used in applyEdits.

supportsRollbackOnFailure Boolean

Indicates if the rollbackOnFailureEnabled parameter can be set to true or false when editing features.

supportsUpdateByAnonymous Boolean

Indicates if anonymous users can update features created by others.

supportsUpdateByOthers Boolean

Indicates if logged in users can update features created by others.

supportsUpdateWithoutM Boolean

Indicates if m-values must be provided when updating features.

supportsUploadWithItemId Boolean

Indicates if the layer supports uploading attachments by UploadId.

metadata Object

Describes the metadata contained on features in the layer.

Specification:
supportsAdvancedFieldProperties Boolean

Indicates whether to provide a user-defined field description. See Describe attribute fields for additional information.

operations Object

Describes operations that can be performed on features in the layer.

Specification:
supportsAdd Boolean

Indicates if new features can be added to the layer.

supportsDelete Boolean

Indicates if features can be deleted from the layer.

supportsUpdate Boolean

Indicates if features in the layer can be updated.

supportsEditing Boolean

Indicates if features in the layer can be edited. Use supportsAdd, supportsUpdate and supportsDelete to determine which editing operations are supported.

supportsCalculate Boolean

Indicates if values of one or more field values in the layer can be updated. See the Calculate REST operation document for more information.

supportsQuery Boolean

Indicates if features in the layer can be queried.

supportsQueryAttachments Boolean

Indicates if the layer supports REST API queryAttachments operation, which is supported with hosted feature services at version 10.5 and greater. If false, queryAttachments() method can only return attachments for one feature at a time. If true, queryAttachments() can return attachments for array of objectIds.

supportsValidateSql Boolean

Indicates if the layer supports a SQL-92 expression or where clause. This operation is only supported in ArcGIS Online hosted feature services.

supportsResizeAttachments Boolean

Indicates if resized attachments are supported in the feature layer. This is useful for showing thumbnails in Popups.

query Object

Describes query operations that can be performed on features in the layer.

Specification:
maxRecordCount Number

The maximum number of records that will be returned for a given query.

supportsCentroid Boolean

Indicates if the geometry centroid associated with each polygon feature can be returned. This operation is only supported in ArcGIS Online hosted feature services.

supportsDistance Boolean

Indicates if the layer's query operation supports a buffer distance for input geometries.

supportsDistinct Boolean

Indicates if the layer supports queries for distinct values based on fields specified in the outFields.

supportsDisjointSpatialRelationship Boolean

Indicates if the query operation supports disjoint spatial relationship. This is valid only for hosted feature services.

supportsCacheHint Boolean

Indicates if the query operation supports a cache hint. This is valid only for hosted feature services.

supportsExtent Boolean

Indicates if the layer's query response includes the extent of features. At 10.3, this option is only available for hosted feature services. At 10.3.1, it is available for hosted and non-hosted feature services.

supportsGeometryProperties Boolean

Indicates if the layer's query response contains geometry attributes, including shape area and length attributes. This operation is supported in ArcGIS Online hosted feature services created since December 2016 and ArcGIS Enterprise feature services since version 10.7.

supportsHavingClause Boolean

Indicates if the layer supports the having clause on the service. Requires an ArcGIS Server service 10.6.1 or greater.

supportsOrderBy Boolean

Indicates if features returned in the query response can be ordered by one or more fields. Requires an ArcGIS Server service 10.3 or greater.

supportsPagination Boolean

Indicates if the query response supports pagination. Requires an ArcGIS Server service 10.3 or greater.

supportsQueryGeometry Boolean

Indicates if the query response includes the query geometry. This is valid only for hosted feature services.

supportsQuantization Boolean

Indicates if the query operation supports the projection of geometries onto a virtual grid. Requires an ArcGIS Server service 10.6.1 or greater.

supportsQuantizationEditMode Boolean

Indicates if the query operation supports quantization designed to be used in edit mode (highest resolution at the given spatial reference). Requires an ArcGIS Server service 10.6.1 or greater.

supportsResultType Boolean

Indicates if the number of features returned by the query operation can be controlled.

supportsSqlExpression Boolean

Indicates if the query operation supports SQL expressions.

supportsStandardizedQueriesOnly Boolean

Indicates if the query operation supports using standardized queries. Learn more about standardized queries here.

supportsStatistics Boolean

Indicates if the layer supports field-based statistical functions. Requires ArcGIS Server service 10.1 or greater.

supportsHistoricMoment Boolean

Indicates if the layer supports historic moment query. Requires ArcGIS Server service 10.5 or greater.

queryRelated Object

Indicates if the layer's query operation supports querying features or records related to features in the layer.

Specification:
supportsCount Boolean

Indicates if the layer's query response includes the number of features or records related to features in the layer.

supportsOrderBy Boolean

Indicates if the related features or records returned in the query response can be ordered by one or more fields. Requires ArcGIS Server service 10.3 or greater.

supportsPagination Boolean

Indicates if the query response supports pagination for related features or records. Requires ArcGIS Server service 10.3 or greater.

Example:
// Once the layer loads, check if the
// supportsAdd operations is enabled on the layer
featureLayer.when(function(){
  if (featureLayer.capabilities.operations.supportsAdd) {
    // if new features can be created in the layer
    // set up the UI for editing
    setupEditing();
  }
});
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.

definitionExpression String

The SQL where clause used to filter features on the client.

elevationInfo Object inherited

Specifies how features are placed on the vertical axis (z). This property may only be used in a SceneView. See the ElevationInfo sample for an example of how this property may be used.

Properties:
mode String

Defines how the feature is placed with respect to the terrain surface. If the geometry consists of multiple points (e.g. lines or polygons), the elevation is evaluated separately for each point. See the table below for a list of possible values.

ModeDescription
on-the-groundFeatures are draped on the terrain surface. This is the default value for features with Polyline or Polygon geometries and features with Point geometries rendered with ObjectSymbol3DLayers.
relative-to-groundFeatures are placed at an elevation relative to the terrain surface. The feature's elevation is determined by summing up the terrain elevation and the geometry's z-value (if present). If featureExpressionInfo is defined, the result of the expression is used instead of the geometry’s z-value. relative-to-ground is the default value for Point geometries rendered with IconSymbol3DLayers.
absolute-heightFeatures are placed at an absolute elevation (z-value) above sea level. This z-value is determined by the geometry's z-value (if present). If featureExpressionInfo is defined, the result of the expression is used instead of the geometry’s z-value. This mode doesn't take the elevation of the terrain into account. This is the default value of features with any geometry type where hasZ is true.
relative-to-sceneFeatures are aligned to extruded polygons and objects part of 3D Object SceneLayers or IntegratedMeshLayers, depending on which has higher elevation. If the feature is not directly above a building or any other feature, it is aligned to the terrain surface elevation. If defined, the result of featureExpressionInfo is added to the 3D Object/terrain surface elevation. In this mode z-values are ignored.
offset Number
optional

An elevation offset, which is added to the vertical position of the feature. If unit is not defined, the offset is in meters. When mode = "on-the-ground", this property has no effect.

featureExpressionInfo Object
optional

This object contains information about setting a custom z-value on the feature.

Specification:
expression String
optional

An Arcade expression evaluating to a number that determines the z-value of the feature. If the geometry has z-values, they will be ignored and featureExpressionInfo will be used to calculate the vertical position of the feature. When mode = "on-the-ground", this property has no effect. For line and polygon geometries the result of the expression is the same for all vertices of a feature.

unit String
optional

The unit for featureExpressionInfo and offset values. It doesn't apply to z-values.

Since: ArcGIS API for JavaScript 4.4

Configures the method for reducing the number of point features in the view. By default this property is null, which indicates the layer view should draw every feature.

StreamLayer supports one type feature reduction: selection. Selection only applies to points in a SceneView and involves thinning overlapping features so no features intersect on screen.

See also:
Example:
// thins features in the view
layer.featureReduction = {
  type: "selection"
};
fieldsIndex FieldsIndexreadonly inherited
Since: ArcGIS API for JavaScript 4.12

A convenient property that can be used to make case-insensitive lookups for a field by name. It can also provide a list of the date fields in a layer.

Example:
// lookup a field by name. name is case-insensitive
const field = layer.fieldsIndex.get("SoMeFiEld");

if (field) {
  console.log(field.name); // SomeField
}
geometryDefinition Extent

An extent object used to filter features. Only features intersecting the extent are displayed in the view.

geometryType Stringreadonly

The geometry type of features in the layer.

Possible Values:"point"|"multipoint"|"polyline"|"polygon"

The unique ID assigned to the layer. If not set by the developer, it is automatically generated when the layer is loaded.

Autocasts from Object[]

The label definition for this layer, specified as an array of LabelClass. Use this property to specify labeling properties for the layer such as label expression, placement, and size.

Multiple Label classes with different where clauses can be used to define several labels with varying styles on the same feature. Likewise, multiple label classes may be used to label different types of features (for example blue labels for boats and green labels for trucks).

Known Limitations

See also:
Example:
const boatLabelClass = new LabelClass({
  labelExpressionInfo: { expression: "$feature.NAME" },
  symbol: {
    type: "label-3d",  // autocasts as new LabelSymbol3D()
    symbolLayers: [{
      type: "text",  // autocasts as new TextSymbol3DLayer()
      material: { color: [ 49,163,84 ] },
      size: 12  // points
    }]
  }
});

streamLayer.labelingInfo = [ boatLabelClass ];
labelsVisible Boolean

Indicates whether to display labels for this layer. If true, labels will appear as defined in the labelingInfo property.

Default Value:true
legendEnabled Boolean inherited

Indicates whether the layer will be included in the legend.

Default Value:true
listMode String inherited

Indicates how the layer should display in the LayerList widget. The possible values are listed below.

ValueDescription
showThe layer is visible in the table of contents.
hideThe layer is hidden in the table of contents.
hide-childrenIf the layer is a GroupLayer, BuildingSceneLayer, KMLLayer, MapImageLayer, TileLayer or WMSLayer, hide the children layers from the table of contents.

Possible Values:"show"|"hide"|"hide-children"

Default Value:show
loaded Booleanreadonly inherited

Indicates whether the layer's resources have loaded. When true, all the properties of the object can be accessed.

Default Value:false
loadError Errorreadonly inherited

The Error object returned if an error occurred while loading.

Default Value:null
loadStatus Stringreadonly inherited

Represents the status of a load operation.

ValueDescription
not-loadedThe object's resources have not loaded.
loadingThe object's resources are currently loading.
loadedThe object's resources have loaded without errors.
failedThe object's resources failed to load. See loadError for more details.

Possible Values:"not-loaded"|"loading"|"failed"|"loaded"

Default Value:not-loaded
loadWarnings Object[]readonly inherited

A list of warnings which occurred while loading.

maximumTrackPoints Number

Maximum number of features to show per trackId. If trackId is not configured on the GeoEvent Service, the maximumTrackPoints property will have no effect and an error will be logged in the console.

maxScale Number inherited

The maximum scale (most zoomed in) at which the layer is visible in the view. If the map is zoomed in beyond this scale, the layer will not be visible. A value of 0 means the layer does not have a maximum scale. The maxScale value should always be smaller than the minScale value, and greater than or equal to the service specification.

Default Value:0
Examples:
// The layer will not be visible when the view is zoomed in beyond a scale of 1:1,000
layer.maxScale = 1000;
// The layer's visibility is not restricted to a maximum scale.
layer.maxScale = 0;
minScale Number inherited

The minimum scale (most zoomed out) at which the layer is visible in the view. If the map is zoomed out beyond this scale, the layer will not be visible. A value of 0 means the layer does not have a minimum scale. The minScale value should always be larger than the maxScale value, and lesser than or equal to the service specification.

Default Value:0
Examples:
// The layer will not be visible when the view is zoomed out beyond a scale of 1:3,000,000
layer.minScale = 3000000;
// The layer's visibility is not restricted to a minimum scale.
layer.minScale = 0;
objectIdField String

The name of an oid field containing a unique value or identifier for each feature in the layer.

See also:

The opacity of the layer. This value can range between 1 and 0, where 0 is 100 percent transparent and 1 is completely opaque.

Default Value:1
Example:
// Makes the layer 50% transparent
layer.opacity = 0.5;
popupEnabled Boolean inherited

Indicates whether to display popups when features in the layer are clicked. The layer needs to have a popupTemplate to define what information should be displayed in the popup. Alternatively, a default popup template may be automatically used if Popup.defaultPopupTemplateEnabled is set to true.

Default Value:true
See also:

The popup template for the layer. When set on the layer, the popupTemplate allows users to access attributes and display their values in the view's popup when a feature is selected using text and/or charts. See the PopupTemplate sample for an example of how PopupTemplate interacts with a FeatureLayer.

A default popup template is automatically used if no popupTemplate has been defined when Popup.defaultPopupTemplateEnabled is set to true.

See also:
purgeOptions Object

Options for purging stale features. Use these options to avoid overloading the browser with graphics.

Properties:
displayCount Number

The maximum number of features to display. Excess features are purged from the beginning of the graphics array.

age Number

The maximum time in minutes that a feature should be kept. After this time, the feature is removed from the layer.

The renderer assigned to the layer. The renderer defines how to visualize each feature in the layer. Depending on the renderer type, features may be visualized with the same symbol, or with varying symbols based on the values of provided attribute fields or functions.

However, when creating a FeatureLayer from client-side features, this property must be specified in the layer's constructor along with the source, fields, objectIdField properties.

See also:
Example:
// all features in the layer will be visualized with
// a 6pt black marker symbol and a thin, white outline
layer.renderer = {
  type: "simple",  // autocasts as new SimpleRenderer()
  symbol: {
    type: "simple-marker",  // autocasts as new SimpleMarkerSymbol()
    size: 6,
    color: "black",
    outline: {  // autocasts as new SimpleLineSymbol()
      width: 0.5,
      color: "white"
    }
  }
};
screenSizePerspectiveEnabled Boolean inherited
Since: ArcGIS API for JavaScript 4.4

Apply perspective scaling to screen-size point symbols in a SceneView. When true, screen sized objects such as icons, labels or callouts integrate better in the 3D scene by applying a certain perspective projection to the sizing of features. This only applies when using a SceneView.

layer.screenSizePerspectiveEnabled = true

screen-size-perspective

layer.screenSizePerspectiveEnabled = false

no-screen-size-perspective

Known Limitations

Screen size perspective is currently not optimized for situations where the camera is very near the ground, or for scenes with point features located far from the ground surface. In these cases it may be better to turn off screen size perspective. As screen size perspective changes the size based on distance to the camera, it should be set to false when using size visual variables.

Default Value:true
See also:
sourceJSON Object
Since: ArcGIS API for JavaScript 4.13

The stream service's metadata JSON exposed by the ArcGIS REST API. While most commonly used properties are exposed on the StreamLayer class directly, this property gives access to all information returned by the stream service. This property is useful if working in an application built using an older version of the API which requires access to stream service properties from a more recent version.

The spatial reference of the layer. When creating the layer from a url, the spatial reference is read from the service.

When creating a FeatureLayer from client-side features, this property is inferred from the geometries of the features provided in the source property.

Since: ArcGIS API for JavaScript 4.14

The layer's time extent. When the layer's useViewTime is false, the layer instructs the view to show data from the layer based on this time extent. If the useViewTime is true, then this property has no effect on the layer, because the layer will show the data within the view's timeExtent property.

Default Value:null
Examples:
if (!layer.useViewTime) {
  if (layer.timeExtent) {
    console.log("Current timeExtent:", layer.timeExtent.start, " - ", layer.timeExtent.end}
  } else {
    console.log("The layer will display data within the view's timeExtent.");
    console.log("Current view.timeExtent:", view.timeExtent.start, " - ", view.timeExtent.end}
  }
}
// set the timeExtent on the layer and useViewTime false
// In this case, the layer will honor its timeExtent and ignore
// the view's timeExtent
const layer = new ImageryLayer({
  url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/ScientificData/SeaTemperature/ImageServer",
  timeExtent: {
    start: new Date(2014, 4, 18),
    end: new Date(2014, 4, 19)
  },
  useViewTime: false
});
Since: ArcGIS API for JavaScript 4.11

TimeInfo provides information such as date fields that store start and end time for each feature and the fullTimeExtent for the layer. The timeInfo property, along with its startField and endField properties, must be set at the time of layer initialization if it is being set for a GeoJSONLayer, CSVLayer or FeatureLayer initialized from client-side features. The fullTimeExtent for timeInfo is automatically calculated based on its startField and endField properties. The timeInfo parameters cannot be changed after the layer is loaded.

Default Value:null
Example:
// create geojson layer from usgs earthquakes geojson feed
const geojsonLayer = new GeoJSONLayer({
  url: "https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_month.geojson",
  copyright: "USGS Earthquakes",
  fields: [
    { "name": "mag", "type": "double" },
    { "name": "place", "type": "string" },
    { "name": "time", "type": "date" }, // date field
    { "name": "depth", "type": "double" }
  ],
  // timeInfo can be used to do temporal queries
  // set the startField and endField.
  // timeExtent is automatically calculated from the
  // the start and end date fields
  timeInfo: {
    startField: "time"
  }
});
Since: ArcGIS API for JavaScript 4.14

A temporary offset of the time data based on a certain TimeInterval. This allows users to overlay features from two or more time-aware layers with different time extents. For example, if a layer has data recorded for the year 1970, an offset value of 2 years would temporarily shift the data to 1972. You can then overlay this data with data recorded in 1972. A time offset can be used for display purposes only. The query and selection are not affected by the offset.

Default Value:null
Example:
// Offset a CSV Layer containing hurricanes from 2015 so that they appear in 2019 (+4 years).
var layer = new CSVLayer({
  url: `hurricanes-and-storms-2015.csv`,
  timeOffset: {
    value: 4,
    unit: "years"
  },
  timeInfo: {
    startField: "ISO_time"
  },
  renderer: {
    type: "simple",
    symbol: {
      type: "simple-marker",
      size: 6,
      color: "red",
      outline: {
        width: 0.5,
        color: "black"
      }
    }
  }
});

The title of the layer used to identify it in places such as the Legend and LayerList widgets.

When loading a layer by service url, the title is derived from the service name. If the service has several layers, then the title of each layer will be the concatenation of the service name and the layer name. When the layer is loaded from a portal item, the title of the portal item will be used instead. Finally, if a layer is loaded as part of a webmap or a webscene, then the title of the layer as stored in the webmap/webscene will be used.

type Stringreadonly

For StreamLayer the type is always "stream".

url String

The URL of the stream service. This is set in the url parameter of the constructor.

Example:
var layer = new StreamLayer({
 url: "https://geoeventsample3.esri.com:6443/arcgis/rest/services/SeattleBus/StreamServer"
});
useViewTime Boolean inherited
Since: ArcGIS API for JavaScript 4.14

Determines if the layer will update its temporal data based on the view's current timeExtent. When false, the layer will display its temporal data based on the layer's timeExtent, regardless of changes to the view.

Default Value:true
Example:
if (featureLayer.useViewTime) {
  console.log("Displaying data between:", view.timeExtent.start, " - ", view.timeExtent.end);
}
version Numberreadonly inherited

The version of ArcGIS Server in which the layer is published.

Example:
// Prints the version number to the console - e.g. 10.2, 10.3, 10.41, etc.
console.log(layer.version);

Indicates if the layer is visible in the View. When false, the layer may still be added to a Map instance that is referenced in a view, but its features will not be visible in the view.

Default Value:true
Example:
// The layer is no longer visible in the view
layer.visible = false;

Method Overview

NameReturn TypeSummaryClass

Cancels a load() operation if it is already in progress.

more details
more detailsLayer
Promise<LayerView>

Called by the views, such as MapView and SceneView, when the layer is added to the Map.layers collection and a layer view must be created for it.

more details
more detailsLayer
PopupTemplate

Creates a popup template for the layer, populated with all the fields of the layer.

more details
more detailsFeatureLayer
Boolean

Emits an event on the instance.

more details
more detailsLayer
Field

Returns the Field instance for a field name (case-insensitive).

more details
more detailsFeatureLayer
Boolean

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

more details
more detailsLayer
Boolean

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

more details
more detailsLayer
Boolean

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

more details
more detailsLayer
Boolean

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

more details
more detailsLayer
Promise

Loads the resources referenced by this class.

more details
more detailsLayer
Object

Registers an event handler on the instance.

more details
more detailsLayer
Promise

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

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more detailsLayer

Method Details

cancelLoad()inherited

Cancels a load() operation if it is already in progress.

createLayerView(view, options){Promise<LayerView>}inherited

Called by the views, such as MapView and SceneView, when the layer is added to the Map.layers collection and a layer view must be created for it. This method is used internally and there is no use case for invoking it directly.

Parameters:
view *

The parent view.

options Object
optional

An object specifying additional options. See the object specification table below for the required properties of this object.

Specification:
optional

A signal to abort the creation of the layerview.

Returns:
TypeDescription
Promise<LayerView>Resolves with a LayerView instance.
See also:
createPopupTemplate(options){PopupTemplate}inherited
Since: ArcGIS API for JavaScript 4.11

Creates a popup template for the layer, populated with all the fields of the layer.

Parameters:
Specification:
options Object
optional

Options for creating the popup template.

Specification:
maximumFields Number
optional
Default Value: 75

The maximum number of fields to include in the popup template.

ignoreFieldTypes String[]
optional

Field types to ignore when creating the popup. By default the geometry, blob, raster, guid and xml field types are ignored.

Returns:
TypeDescription
PopupTemplateThe popup template, or null if the layer does not have any fields.
emit(type, event){Boolean}inherited
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
optional

The event payload.

Returns:
TypeDescription
Booleantrue if a listener was notified
getField(fieldName){Field}inherited
Since: ArcGIS API for JavaScript 4.11

Returns the Field instance for a field name (case-insensitive).

Parameter:
fieldName String

Name of the field.

Returns:
TypeDescription
Fieldthe matching field or undefined
See also:
hasEventListener(type){Boolean}inherited

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:
TypeDescription
BooleanReturns true if the class supports the input event.
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:
TypeDescription
BooleanIndicates 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:
TypeDescription
BooleanIndicates 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:
TypeDescription
BooleanIndicates whether creating an instance of the class has been resolved.
load(signal){Promise}inherited

Loads the resources referenced by this class. This method automatically executes for a View and all of the resources it references in Map if the view is constructed with a map instance.

This method must be called by the developer when accessing a resource that will not be loaded in a View.

It's possible to provide a signal to stop being interested into a Loadable instance load status. When the signal is aborted, the instance does not stop its loading process, only cancelLoad can abort it.

Parameter:
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:
TypeDescription
PromiseResolves when the resources have loaded.
on(type, listener){Object}inherited

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

Parameters:

A event type, or an array of event types, to listen for.

listener Function

The function to call when the event is fired.

Returns:
TypeDescription
ObjectReturns an event handler with a remove() method that can be called to stop listening for the event(s).
PropertyTypeDescription
removeFunctionWhen 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);
});
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:
TypeDescription
PromiseReturns 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

NameTypeSummaryClass
{view: View,layerView: LayerView}

Fires after the layer's LayerView is created and rendered in a view.

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more detailsLayer
{view: View,error: Error}

Fires when an error emits during the creation of a LayerView after a layer has been added to the map.

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more detailsLayer
{view: View,layerView: LayerView}

Fires after the layer's LayerView is destroyed and no longer renders in a view.

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Event Details

layerview-createinherited

Fires after the layer's LayerView is created and rendered in a view.

Properties:
view View

The view in which the layerView was created.

layerView LayerView

The LayerView rendered in the view representing the layer in layer.

See also:
Example:
// This function will fire each time a layer view is created for this
// particular view.
layer.on("layerview-create", function(event){
  // The LayerView for the layer that emitted this event
  event.layerView;
});
layerview-create-errorinherited

Fires when an error emits during the creation of a LayerView after a layer has been added to the map.

Properties:
view View

The view that failed to create a layerview for the layer emitting this event.

error Error

An error object describing why the layer view failed to create.

See also:
Example:
// This function fires when an error occurs during the creation of the layer's layerview
layer.on("layerview-create-error", function(event) {
  console.error("LayerView failed to create for layer with the id: ", layer.id, " in this view: ", event.view);
});
layerview-destroyinherited

Fires after the layer's LayerView is destroyed and no longer renders in a view.

Properties:
view View

The view in which the layerView was destroyed.

layerView LayerView

The destroyed LayerView representing the layer.

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