ParquetLayer | API Reference | ArcGIS Maps SDK for JavaScript

The ParquetLayer enables visualization of Parquet files on a map. Parquet is a columnar storage format optimized for efficiently handling big data and distributed environments. Its columnar structure, compression capabilities, and schema support make it ideal for analytics and query-heavy workloads.

The ParquetLayer can represent either spatial data (with geographic features) or non-spatial data as a table. If the Parquet file contains spatial data, then rows can be rendered as features with geometries in a Map component or a MapView. If not, they can still be shown in a table. A non-spatial layer is a table which does not have a spatial column representing geographic features.

Parquet files must use either GZIP or Snappy compression, or no compression. Files using other compression formats are not supported. Geometry encoding must be specified when it cannot be automatically inferred. For details on supported formats and how to configure encoding manually or rely on auto-detection, see the encoding property.

ParquetLayers may be created by either:

Specifying the URLs of the Parquet files.

The ParquetLayer can be loaded by setting its urls property to the urls of the Parquet files. The following snippet shows how to add a new ParquetLayer to the map.

// Add the Parquet files from given urls as a parquet layer.
const layer = new ParquetLayer({
  urls: [
    "url-to-parquet-file1.parquet",
    "url-to-parquet-file2.parquet"
  ]
});
map.add(layer);

Using the parquetUtils.getParquetLayerInfo()

Use the parquetUtils.getParquetLayerInfo() method to retrieve information needed to create a parquet layer from the first Parquet file in the specified URLs array. The following snippet shows how to create a new ParquetLayer using the retrieved information returned from the getParquetLayerInfo().

// get parquet layer info from the first Parquet file in the urls array
const urls = ["url-to-your-parquet-file.parquet", "url-to-your-parquet-file2.parquet"];
const info = await parquetUtils.getParquetLayerInfo(urls);
const layer = new ParquetLayer(info);

// create a renderer based on the geometry type
if (info.geometryType === "polygon") {
  const renderer = new SimpleRenderer({
    symbol: {
      type: "simple-fill",
      color: [227, 139, 79, 0.8],
      outline: {
        color: [255, 255, 255],
        width: 1
      }
    }
  });
  layer.renderer = renderer;
}
// add the layer to the map
map.add(layer);

Known Limitations

The ParquetLayer is supported in a Map component or a MapView.
The ParquetLayer only supports geographic (WGS84) and Web Mercator spatial references.
Time and date fields may be downgraded to numeric values.
The ParquetLayer does not support the outStatistics, orderByFields, or returnDistinctValues query parameters when the layer has more than 20,000 features.

See also

Constructors

ParquetLayer Constructor new ParquetLayer(properties)

Parameter

properties Object

optional

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

Example

const layer = new ParquetLayer({
   urls: [
     "https://example.com/path/to/parquetfile1.parquet",
     "https://example.com/path/to/parquetfile2.parquet"
   ]
});
mapElement.map.add(layer);  // adds the layer to the map

Property Overview

Any properties can be set, retrieved or listened to. See the Watch for changes topic.

Show inherited properties

Hide inherited properties

Type	Summary	Class
String	Blend modes are used to blend layers together to create an interesting effect in a layer, or even to produce what seems like a new layer.	ParquetLayer
Capabilities\|null\|undefined	Describes the layer's supported capabilities.	ParquetLayer
String\|null\|undefined	Copyright information for the layer.	ParquetLayer
Object\|null\|undefined	A list of custom parameters appended to the URL of all resources fetched by the layer.	ParquetLayer
String	The name of the class.	Accessor
Effect\|null\|undefined	Effect provides various filter functions that can be performed on the layer to achieve different visual effects similar to how image filters work.	ParquetLayer
ParquetEncodingWkb\|ParquetEncodingLocation\|null\|undefined	The encoding format used to store geometries in the Parquet files.	ParquetLayer
FeatureEffect\|null\|undefined	The featureEffect can be used to draw attention to features of interest.	ParquetLayer
FeatureReductionBinning\|FeatureReductionCluster\|FeatureReductionSelection\|null\|undefined	Configures the method for reducing the number of features in the view.	ParquetLayer
Field []	An array of fields in the layer.	ParquetLayer
FieldsIndex	A convenient property that can be used to make case-insensitive lookups for a field by name.	ParquetLayer
Extent\|null\|undefined	The full extent of the layer.	Layer
String\|null\|undefined	The geometry type of features in the layer.	ParquetLayer
String	The unique ID assigned to the layer.	Layer
Boolean	Returns `true` if the layer is loaded from a Parquet file without spatial data.	ParquetLayer
LabelClass []\|null\|undefined	The label definition for this layer, specified as an array of LabelClass.	ParquetLayer
Boolean	Indicates whether to display labels for this layer.	ParquetLayer
String	Indicates how the layer should display in the Layer List component.	Layer
Error\|null\|undefined	The Error object returned if an error occurred while loading.	Layer
String	Represents the status of a load operation.	Layer
Object []	A list of warnings which occurred while loading.	Layer
Boolean	Indicates whether the layer's resources have loaded.	Layer
Number	The maximum scale (most zoomed in) at which the layer is visible in the view.	ParquetLayer
Number	The minimum scale (most zoomed out) at which the layer is visible in the view.	ParquetLayer
String	The name of an `oid`field containing a unique value or identifier for each feature in the layer.	ParquetLayer
Number	The opacity of the layer.	Layer
OrderByInfo []\|null\|undefined	Determines the order in which features are drawn in the view.	ParquetLayer
String []\|null\|undefined	An array of field names from the service to include with each feature.	ParquetLayer
Map\|Basemap\|Ground\|GroupLayer\|CatalogDynamicGroupLayer\|CatalogLayer\|null\|undefined	The parent to which the layer belongs.	Layer
Boolean	Enable persistence of the layer in a WebMap or WebScene.	ParquetLayer
Boolean	Indicates whether to display popups when features in the layer are clicked.	ParquetLayer
PopupTemplate\|null\|undefined	The popup template for the layer.	ParquetLayer
RendererUnion\|null\|undefined	The renderer assigned to the layer.	ParquetLayer
SpatialReference	The spatial reference of the layer.	ParquetLayer
String\|null\|undefined	The title of the layer used to identify it in places such as the Layer List component.	Layer
String	For ParquetLayer the type is always "parquet".	ParquetLayer
String	An automatically generated unique identifier assigned to the instance.	Layer
Collection<string>	Collection of urls for Parquet files.	ParquetLayer
Boolean	Indicates if the layer is visible in the View.	Layer

Property Details

blendMode Property blendMode String

Blend modes are used to blend layers together to create an interesting effect in a layer, or even to produce what seems like a new layer. Unlike the method of using transparency which can result in a washed-out top layer, blend modes can create a variety of very vibrant and intriguing results by blending a layer with the layer(s) below it.

When blending layers, a top layer is a layer that has a blend mode applied. All layers underneath the top layer are background layers. The default blending mode is normal where the top layer is simply displayed over the background layer. While this default behavior is perfectly acceptable, the use of blend modes on layers open up a world of endless possibilities to generate creative maps.

The layers in a GroupLayer are blended together in isolation from the rest of the map.

In the following screenshots, the vintage shaded relief layer is displayed over a firefly world imagery layer. The color blend mode is applied to the vintage shaded relief and the result looks like a new layer.

Known Limitations

In 3D SceneViews, the blendMode is supported on BaseTileLayer, ImageryTileLayer, OpenStreetMapLayer, TileLayer, VectorTileLayer, WCSLayer, WebTileLayer, WMTSLayer and GroupLayer.
The blendMode is not supported in the Legend.
When working with GroupLayers in a 3D SceneView, the blendMode is only applied to the sublayers that support it.
See print for known printing limitations.

The following factors will affect the blend result:

Order of all layers
Layer opacity
Opacity of features in layers
Visibility of layers
By default, the very bottom layer in a map is drawn on a transparent background. You can change the MapView's background color.

Blend mode	Description
normal	The top layer is displayed over the background layer. The data of the top layer block the data of background layer where they overlap.
average	Takes the mathematical average of top and background layers. Result of `average` blend mode is often similar to the effect of setting the layer's opacity to 50%.

Lighten blend modes:

The following blend modes create lighter results than all layers. In lighten blend modes, pure black colors in the top layer become transparent allowing the background layer to show through. White in the top layer will stay unchanged. Any color that is lighter than pure black is going to lighten colors in the top layer to varying degrees all way to pure white.

Lighten blend modes can be useful when lightening dark colors of the top layer or removing black colors from the result. The plus, lighten and screen modes can be used to brighten layers that have faded or dark colors on a dark background.

Blend mode	Description
lighten	Compares top and background layers and retains the lighter color. Colors in the top layer become transparent if they are darker than the overlapping colors in the background layer allowing the background layer to show through completely. Can be thought of as the opposite of `darken` blend mode.
lighter	Colors in top and background layers are multiplied by their alphas (layer opacity and layer's data opacity. Then the resulting colors are added together. All overlapping midrange colors are lightened in the top layer. The opacity of layer and layer's data will affect the blend result.
plus	Colors in top and background layers are added together. All overlapping midrange colors are lightened in the top layer. This mode is also known as `add` or `linear-dodge`.
screen	Multiplies inverted colors in top and background layers then inverts the colors again. The resulting colors will be lighter than the original color with less contrast. Screen can produce many different levels of brightening depending on the luminosity values of the top layer. Can be thought of as the opposite of the `multiply` mode.
color-dodge	Divides colors in background layer by the inverted top layer. This lightens the background layer depending on the value of the top layer. The brighter the top layer, the more its color affects the background layer. Decreases the contrast between top and background layers resulting in saturated mid-tones and blown highlights.

Darken blend modes:

The following blend modes create darker results than all layers. In darken blend modes, pure white in the top layer will become transparent allowing the background layer to show through. Black in the top layer will stay unchanged. Any color that is darker than pure white is going to darken a top layer to varying degrees all the way to pure black.

The multiply blend mode is often used to highlight shadows, show contrast, or accentuate an aspect of a map. For example, you can use multiply blend mode on a topographic map displayed over hillshade when you want to have your elevation show through the topographic layer. See the intro to layer blending sample.

The multiply and darken modes can be used to have dark labels of the basemap to show through top layers. See the darken blending sample.

The color-burn mode works well with colorful top and background layers since it increases saturation in mid-tones. It increases the contrast by tinting pixels in overlapping areas in top and bottom layers more towards the top layer color. Use this blend mode, when you want an effect with more contrast than multiply or darken.

The following screenshots show how the multiply blend mode used for creating a physical map of the world that shows both boundaries and elevation. multiply-blend

Blend mode	Description
darken	Emphasizes the darkest parts of overlapping layers. Colors in the top layer become transparent if they are lighter than the overlapping colors in the background layer, allowing the background layer to show through completely.
multiply	Emphasizes the darkest parts of overlapping layers by multiplying colors of the top layer and the background layer. Midrange colors from top and background layers are mixed together more evenly.
color-burn	Intensifies the dark areas in all layers. It increases the contrast between top and background layers, by tinting colors in overlapping area towards the top color. To do this it inverts colors of the background layer, divides the result by colors of the top layer, then inverts the results.

Contrast blend modes:

The following blend modes create contrast by both lightening the lighter areas and darkening the darker areas in the top layer by using lightening or darkening blend modes to create the blend. The contrast blend modes will lighten the colors lighter than 50% gray ([128,128,128]), and darken the colors darker than 50% gray. 50% gray will be transparent in the top layer. Each mode can create a variety of results depending on the colors of top and background layers being blended together. The overlay blend mode makes its calculations based on the brightness of the colors in the background layer while all of the other contrast blend modes make their calculations based on the brightness of the top layer. Some of these modes are designed to simulate the effect of shining a light through the top layer, effectively projecting upon the layers beneath it.

Contrast blend modes can be used to increase the contrast and saturation to have more vibrant colors and give a punch to your layers. For example, you can duplicate a layer and set overlay blend mode on the top layer to increase the contrast and tones of your layer. You can also add a polygon layer with a white fill symbol over a dark imagery layer and apply soft-light blend mode to increase the brightness in the imagery layer.

The following screenshots show an effect of the overlay blend mode on a GraphicsLayer. The left image shows when the buffer graphics layer has the normal blend mode. As you can see, the gray color for the buffer polygon is blocking the intersecting census tracts. The right image shows when the overlay blend mode is applied to the buffer graphics layer. The overlay blend mode darkens or lightens the gray buffer polygon depending on the colors of the background layer while the census tracts layer is shining through. See this in action.

Normal blend mode	Overlay blend mode

Blend mode	Description
overlay	Uses a combination of `multiply` and `screen` modes to darken and lighten colors in the top layer with the background layer always shining through. The result is darker color values in the background layer intensify the top layer, while lighter colors in the background layer wash out overlapping areas in the top layer.
soft-light	Applies a half strength `screen` mode to lighter areas and half strength `multiply` mode to darken areas of the top layer. You can think of the `soft-light` as a softer version of the `overlay` mode.
hard-light	Multiplies or screens the colors, depending on colors of the top layer. The effect is similar to shining a harsh spotlight on the top layer.
vivid-light	Uses a combination of `color-burn` or `color-dodge` by increasing or decreasing the contrast, depending on colors in the top layer.

Component blend modes:

The following blend modes use primary color components, which are hue, saturation and luminosity to blend top and background layers. You can add a feature layer with a simple renderer over any layer and set hue, saturation, color or luminosity blend mode on this layer. With this technique, you create a brand new looking map.

The following screenshots show where the topo layer is blended with world hillshade layer with luminosity blend mode. The result is a drastically different looking map which preserves the brightness of the topo layer while adapting the hue and saturation of the hillshade layer.

Blend mode	Description
hue	Creates an effect with the hue of the top layer and the luminosity and saturation of the background layer.
saturation	Creates an effect with the saturation of the top layer and the hue and luminosity of the background layer. 50% gray with no saturation in the background layer will not produce any change.
luminosity	Creates effect with the luminosity of the top layer and the hue and saturation of the background layer. Can be thought of as the opposite of `color` blend mode.
color	Creates an effect with the hue and saturation of the top layer and the luminosity of the background layer. Can be thought of as the opposite of `luminosity` blend mode.

Composite blend modes:

The following blend modes can be used to mask the contents of top, background or both layers.

Destination modes are used to mask the data of the top layer with the data of the background layer.
Source modes are used to mask the data of the background layer with the data of the top layer.

The destination-in blend mode can be used to show areas of focus such as earthquakes, animal migration, or point-source pollution by revealing the underlying map, providing a bird's eye view of the phenomenon. Check out multiple blending and groupLayer blending samples to see composite blend modes in action.

The following screenshots show feature and imagery layers on the left side on their own in the order they are drawn in the view. The imagery layer that contains land cover classification rasters. The feature layer contains 2007 county crops data. The right image shows the result of layer blending where destination-in blendMode is set on the imagery layer. As you can see, the effect is very different from the original layers. The blended result shows areas of cultivated crops only (where both imagery and feature layers overlap).

Blend mode	Description
destination-over	Destination/background layer covers the top layer. The top layer is drawn underneath the destination layer. You'll see the top layer peek through wherever the background layer is transparent or has no data.
destination-atop	Destination/background layer is drawn only where it overlaps the top layer. The top layer is drawn underneath the background layer. You'll see the top layer peek through wherever the background layer is transparent or has no data.
destination-in	Destination/background layer is drawn only where it overlaps with the top layer. Everything else is made transparent.
destination-out	Destination/background layer is drawn where it doesn't overlap the top layer. Everything else is made transparent.
source-atop	Source/top layer is drawn only where it overlaps the background layer. You will see the background layer peek through where the source layer is transparent or has no data.
source-in	Source/top layer is drawn only where it overlaps with the background layer. Everything else is made transparent.
source-out	Source/top layer is drawn where it doesn't overlap the background layer. Everything else is made transparent.
xor	Top and background layers are made transparent where they overlap. Both layers are drawn normal everywhere else.

Invert blend modes:

The following blend modes either invert or cancel out colors depending on colors of the background layer. These blend modes look for variations between top and background layers. For example, you can use difference or exclusion blend modes on two imagery layers of forest covers to visualize how forest covers changed from one year to another.

The invert blend mode can be used to turn any light basemap into a dark basemap to accommodate those who work in low-light conditions. The following screenshots show how setting the invert blend mode set on a feature layer with a simple renderer turns the world Hillshade into a dark themed basemap in no time.

Blend mode	Description
difference	Subtracts the darker of the overlapping colors from the lighter color. When two pixels with the same value are subtracted, the result is black. Blending with black produces no change. Blending with white inverts the colors. This blending mode is useful for aligning layers with similar content.
exclusion	Similar to the `difference` blend mode, except that the resulting image is lighter overall. Overlapping areas with lighter color values are lightened, while darker overlapping color values become transparent.
minus	Subtracts colors of the top layer from colors of the background layer making the blend result darker. In the case of negative values, black is displayed.
invert	Inverts the background colors wherever the top and background layers overlap. The invert blend mode inverts the layer similar to a photographic negative.
reflect	This blend mode creates effects as if you added shiny objects or areas of light in the layer. Black pixels in the background layer are ignored as if they were transparent.

Default Value:"normal"

See also

Layer blending samples

capabilities Property capabilities Capabilities |null |undefinedreadonly

Describes the layer's supported capabilities.

copyright Property copyright String |null |undefined

customParameters Property customParameters Object |null |undefined

A list of custom parameters appended to the URL of all resources fetched by the layer. It's an object with key-value pairs where value is a string. The layer's refresh() method needs to be called if the customParameters are updated at runtime.

Example

// send a custom parameter to your special service
let layer = new MapImageLayer({
  url: serviceUrl,
  customParameters: {
    "key": "my-special-key"
  }
});

declaredClass Inherited Property declaredClass Stringreadonly Inherited from Accessor

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

effect Property effect Effect |null |undefinedautocast

Effect provides various filter functions that can be performed on the layer to achieve different visual effects similar to how image filters work. This powerful capability allows you to apply css filter-like functions to layers to create custom visual effects to enhance the cartographic quality of your maps. This is done by applying the desired effect to the layer's effect property as a string or an array of objects to set scale dependent effects.

Notes

Set featureEffect property if different effects need to be applied features that meet or fail a specified filter.
If all of the following four properties are applied, then they will be applied in this order: featureEffect, effect, opacity and blendMode.

Known Limitations

The effect is not supported in 3D SceneViews.
The effect cannot be applied to a layer with a heatmap renderer.
The effect is not supported in layers with featureReduction of type cluster enabled.
See print for known printing limitations.

Default Value:null

See also

Examples

// the following effect will be applied to the layer at all scales
// brightness will be applied first, then hue-rotate followed by contrast
// changing order of the effects will change the final result
layer.effect = "brightness(5) hue-rotate(270deg) contrast(200%)";

// set a scale dependent bloom effect on the layer
layer.effect = [
  {
    scale: 36978595,
    value: "drop-shadow(3px, 3px, 4px)"
  },
  {
    scale: 18489297,
    value: "drop-shadow(2px, 2px, 3px)"
  },
  {
    scale: 4622324,
    value: "drop-shadow(1px, 1px, 2px)"
  }
];

encoding Property encoding ParquetEncodingWkb |ParquetEncodingLocation |null |undefinedautocast Since: ArcGIS Maps SDK for JavaScript 4.34 ParquetLayer since 4.33, encoding added at 4.34.

The encoding format used to store geometries in the Parquet files. The geometry encoding is automatically detected if the file contains Geoparquet metadata. If not, the layer will attempt to locate latitude and longitude columns and display those as the geometry. Otherwise, the encoding must be specified manually.

ParquetLayer supports two encoding types:

ParquetEncodingLocation: Used when geometry is stored as coordinate fields. If the file contains coordinate fields named "lng/lat", "lon/lat", "long/lat", "longitude/latitude", "x/y", "xcenter/ycenter", "longitude83/latitude83", "longdecdeg/latdecdeg", "point-x/point-y", these are detected automatically. The field names are case insensitive. For other coordinate field names, set the layer’s encoding to an instance of ParquetEncodingLocation with the coordinate fields specified, and set the layer’s spatialReference and geometryType properties accordingly.
ParquetEncodingWkb: Used when geometry is stored as a WKB-encoded column. Set the layer's encoding to an instance of ParquetEncodingWkb with the geometry column name, and set the layer’s spatialReference (WGS84 or WebMercator) and geometryType properties accordingly.

Example

// ParquetLayer with WKB encoding
const layer = new ParquetLayer({
  urls: ["https://example.com/path/to/parquetfile.parquet"],
  encoding: new ParquetEncodingWkb({
    primaryFieldName: "polyGeometry"
  }), // WKB geometry column
  spatialReference: { wkid: 4326 }, // WGS84
  geometryType: "polygon"
});

featureEffect Property featureEffect FeatureEffect |null |undefinedautocast

The featureEffect can be used to draw attention to 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.

Notes

Set the effect property if the effect needs to be applied to the entire layer.
If the featureEffect is set on the layer, it will be inherited by layerView.featureEffect unless the developer overrides it on the layer view. The layerView.featureEffect will take precedence over layer.featureEffect if both properties are set.
If all of the following four properties are applied, then they will be applied in this order: featureEffect, effect, opacity and blendMode.

Known Limitations

FeatureEffect is not supported in the following scenarios:
- In 3D SceneViews
- When FeatureReductionCluster is enabled
- See print for known printing limitations.

See also

Examples

// gray out features that fall outside of the 3 mile buffer of the mouse's location
// by setting feature effect on excluded features
layer.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'"
});
layer.featureEffect = new FeatureEffect({
  filter: featureFilter,
  includedEffect: "drop-shadow(3px, 3px, 3px, black)",
  excludedEffect: "blur(1px) brightness(65%)"
});

featureReduction Property featureReduction FeatureReductionBinning |FeatureReductionCluster |FeatureReductionSelection |null |undefinedautocast

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

There are three types of feature reduction: selection, cluster, and binning.

Selection only applies to points in a SceneView and involves thinning overlapping features so no features intersect on screen. This has been available since version 4.4.
Cluster groups points, lines, or polygons in a MapView into clusters defined in screen space. Each cluster is a point geometry whose size is proportional to the number of features within the cluster. This has been available since version 4.14.
Binning spatially groups points, lines, or polygons in a MapView into bins, clearly defining the area aggregating features in map space. Each bin is a polygon geometry typically rendered so its color represents the number of features within the bin. This has been available since version 4.24.

See also

Examples

// clusters features based on their spatial proximity to other features
layer.featureReduction = {
  type: "cluster",
  clusterRadius: 100
};

// thins features in the view
layer.featureReduction = {
  type: "selection"
};

// Aggregates features to bins
layer.featureReduction = {
  type: "binning",
  renderer: {
    type: "simple",  // autocasts as new SimpleRenderer()
    symbol: {
      type: "simple-fill",  // autocasts as new SimpleFillSymbol()
      outline: {  // autocasts as new SimpleLineSymbol()
        width: 0.5,
        color: "white"
      }
    },
    visualVariables: [{
      type: "color",
      field: "aggregateCount",
      stops: [
        { value: 1, color: "white" },
        { value: 1000, color: "blue" }
      ]
    }]
  },
  popupTemplate: {
    content: "This bin contains <b>{aggregateCount}</b> features.",
    fieldInfos: [{
      fieldName: "aggregateCount",
      format: {
        digitSeparator: true,
        places: 0
      }
    }]
  }
};

fields Property fields Field[]autocast Autocasts from Object []

An array of fields in the layer.

Notes

The ParquetLayer does not support the date and group type field types.
For details on how big-integer fields are handled, refer to the big-integer documentation.

Example

// define each field's schema
let fields = [
 new Field({
   "name": "ObjectID",
   "alias": "ObjectID",
   "type": "oid"
 }), new Field({
   "name": "description",
   "alias": "Description",
   "type": "string"
 }), new Field ({
   "name": "title",
   "alias": "Title",
   "type": "string"
 })
];

fieldsIndex Property fieldsIndex FieldsIndexreadonly

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
}

fullExtent Inherited Property fullExtent Extent |null |undefinedautocast Inherited from Layer

The full extent of the layer. By default, this is worldwide. This property may be used to set the extent of the view to match a layer's extent so that its features appear to fill the view. See the sample snippet below.

Example

// Once the layer loads, set the view's extent to the layer's fullextent
layer.when(function(){
  view.extent = layer.fullExtent;
});

geometryType Property geometryType String |null |undefined

The geometry type of features in the layer. All features must be of the same type.

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

id Inherited Property id String Inherited from Layer

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

isTable Property isTable Booleanreadonly Since: ArcGIS Maps SDK for JavaScript 4.34 ParquetLayer since 4.33, isTable added at 4.34.

Returns true if the layer is loaded from a Parquet file without spatial data. Non-spatial Parquet files do not have geometry object that represent geographic features. The geometryType of the layer will be null if the isTable is true.

A non-spatial table instance can be created from the urls and the table must be loaded by calling load() method.

Default Value:false

See also

labelingInfo Property labelingInfo LabelClass[] |null |undefinedautocast 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.

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 lakes and green labels for parks).

See also

labelsVisible

Example

const labels = new LabelClass({
  labelExpressionInfo: { expression: "$feature.NAME" },
  symbol: {
    type: "text",  // autocasts as new TextSymbol()
    color: "black",
    haloSize: 1,
    haloColor: "white"
  }
});

layer.labelingInfo = [ labels ];

labelsVisible Property labelsVisible Boolean

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

Default Value:true

listMode Inherited Property listMode String Inherited from Layer

Indicates how the layer should display in the Layer List component. The possible values are listed below.

Value	Description
show	The layer is visible in the table of contents.
hide	The layer is hidden in the table of contents.
hide-children	If the layer is a GroupLayer, BuildingSceneLayer, KMLLayer, MapImageLayer, SubtypeGroupLayer, TileLayer, or WMSLayer, hide the children layers from the table of contents.

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

Default Value:"show"

loadError Inherited Property loadError Error |null |undefinedreadonly Inherited from Layer

The Error object returned if an error occurred while loading.

Default Value:null

loadStatus Inherited Property loadStatus Stringreadonly Inherited from Layer

Represents the status of a load operation.

Value	Description
not-loaded	The object's resources have not loaded.
loading	The object's resources are currently loading.
loaded	The object's resources have loaded without errors.
failed	The object's resources failed to load. See loadError for more details.

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

Default Value:"not-loaded"

loadWarnings Inherited Property loadWarnings Object[]readonly Inherited from Layer

A list of warnings which occurred while loading.

loaded Inherited Property loaded Booleanreadonly Inherited from Layer

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

Default Value:false

maxScale Property maxScale Number

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 Property minScale Number

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 Property objectIdField Stringreadonly

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

See also

fields

opacity Inherited Property opacity Number Inherited from Layer

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

Known Limitations

In a 3D SceneView, modifying opacity is not supported for DimensionLayer, IntegratedMesh3DTilesLayer, IntegratedMeshLayer, LineOfSightLayer, PointCloudLayer, ViewshedLayer, and VoxelLayer.

Default Value:1

Example

// Makes the layer 50% transparent
layer.opacity = 0.5;

orderBy Property orderBy OrderByInfo[] |null |undefinedautocast

Determines the order in which features are drawn in the view. You can sort features by a field value or the value returned from an Arcade expression in ascending or descending order.

When null (default), features are drawn in the order they are returned from the service or client.

Known Limitations

This property only controls feature drawing order in MapView. Configuring feature drawing order in SceneView is not supported.
This property does not control the drawing order of clusters. It only applies to individual features.
Feature drawing order configurations defined with Arcade expressions cannot be saved to web maps.
Currently, you can only sort features by one field or expression.

Default Value:null

See also

Arcade Feature Z Profile

Examples

// Features with smaller population values will
// be rendered on top of larger features.
layer.orderBy = [{
  field: "POPULATION"
}];

// Features with larger population values will
// be rendered on top of smaller features.
layer.orderBy = [{
  field: "POPULATION",
  order: "descending"
}];

// Orders features by date in descending order.
// The most recent features will be rendered
// on top of older features.
layer.orderBy = [{
  field: "Alarm_Date",
  order: "descending"
}];

// Orders features by storm warning duration in descending order.
// Warnings with longer durations
// be rendered on top of warnings with shorter durations.
layer.orderBy = [{
  valueExpression: "DateDiff($feature.Watch_End, $feature.Watch_Start, 'hours' )",
  order: "descending"
}];

// Orders features by data values used in a size visual variable
const sizeVariable = layer.renderer.visualVariables.find( vv => vv.type === "size");
const { field, valueExpression } = sizeVariable;
layer.orderBy = [{
  field,
  valueExpression,
  order: "ascending"
}];

outFields Property outFields String[] |null |undefined

An array of field names from the service to include with each feature. To fetch the values from all fields in the layer, use ["*"]. Fields specified in outFields will be requested alongside with required fields for rendering, labeling and setting the elevation info for the layer. The required fields and outFields are used to populate ParquetLayerView.availableFields.

Default Value:null

See also

Examples

// Includes all fields from the Parquet files in the layer
layer.outFields = ["*"];

// Get the specified fields from the service in the layer
// These fields will be added to ParquetLayerView.availableFields
// along with rendering and labeling fields.
layer.outFields = ["NAME", "POP_2010", "FIPS", "AREA"];

The parent to which the layer belongs.

persistenceEnabled Property persistenceEnabled Boolean

Enable persistence of the layer in a WebMap or WebScene.

Default Value:true

popupEnabled Property popupEnabled Boolean

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

popupTemplate Property popupTemplate PopupTemplate |null |undefinedautocast

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.

Notes

The ParquetLayer's popupTemplate displays only the attributes of the topmost feature when features overlap.

See also

createPopupTemplate
View2D

renderer Property renderer RendererUnion |null |undefinedautocast

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. If not specified, a default renderer will be generated based on the geometry type.

See also

Styles and data visualization

spatialReference Property spatialReference SpatialReferenceautocast

The spatial reference of the layer. The default value is WGS84.

Known Limitations

The ParquetLayer only supports geographic (WGS84) and Web Mercator spatial references.

Default Value:SpatialReference.WGS84

See also

SpatialReference.WGS84

title Inherited Property title String |null |undefined Inherited from Layer

The title of the layer used to identify it in places such as the Layer List component.

If the layer is loaded from a portal item, the title of the portal item will be used. 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 Property type Stringreadonly

For ParquetLayer the type is always "parquet".

uid Inherited Property uid Stringreadonly Inherited from Layer

An automatically generated unique identifier assigned to the instance. The unique id is generated each time the application is loaded.

urls Property urls Collection<string>autocast

Collection of urls for Parquet files.

Example

// create parquet layer from multiple Parquet files
const layer = new ParquetLayer({
  urls: [
    "https://example.com/path/to/parquetfile1.parquet",
    "https://example.com/path/to/parquetfile2.parquet"
  ]
});

visible Inherited Property visible Boolean Inherited from Layer

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;

// Watch for changes in the layer's visibility
// and set the visibility of another layer when it changes
reactiveUtils.watch(
  () => layer.visible,
  (visible) => {
    if (visible) {
      anotherLayer.visible = true;
    } else {
      anotherLayer.visible = false;
    }
  }
);

Method Overview

Show inherited methods

Hide inherited methods

Return Type	Summary	Class
	Adds one or more handles which are to be tied to the lifecycle of the object.	Accessor
	Cancels a load() operation if it is already in progress.	Layer
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.	Layer
PopupTemplate\|null\|undefined	Creates a popup template for the layer, populated with all the fields of the layer.	ParquetLayer
	Destroys the layer and any associated resources (including its portalItem, if it is a property on the layer).	Layer
Boolean	Emits an event on the instance.	Layer
Promise<Object>	Fetches custom attribution data for the layer when it becomes available.	Layer
Field\|null\|undefined	Returns the Field instance for a field name (case-insensitive).	ParquetLayer
Domain\|null\|undefined	Returns the Domain associated with the given field name.	ParquetLayer
Boolean	Indicates whether there is an event listener on the instance that matches the provided event name.	Layer
Boolean	Returns true if a named group of handles exist.	Accessor
Boolean	`isFulfilled()` may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected).	Layer
Boolean	`isRejected()` may be used to verify if creating an instance of the class is rejected.	Layer
Boolean	`isResolved()` may be used to verify if creating an instance of the class is resolved.	Layer
Promise	Loads the resources referenced by this class.	Layer
Object	Registers an event handler on the instance.	Layer
Promise<Object>	Executes a Query against the ParquetLayer and returns the Extent and count of features that satisfy the query.	ParquetLayer
Promise<Number>	Executes a Query against the ParquetLayer and returns the number of features that satisfy the query.	ParquetLayer
Promise<FeatureSet>	Executes a Query against the ParquetLayer and returns a FeatureSet once the promise resolves.	ParquetLayer
Promise<Array<(number\|string)>>	Executes a Query against the ParquetLayer and returns an array of Object IDs for features that satisfy the input query.	ParquetLayer
	Removes a group of handles owned by the object.	Accessor
Promise	`when()` may be leveraged once an instance of the class is created.	Layer

Method Details

addHandles Inherited Method addHandles(handleOrHandles, groupKey) Inherited from Accessor

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.

cancelLoad Inherited Method cancelLoad() Inherited from Layer

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

createLayerView Inherited Method createLayerView(view, options){Promise<LayerView>} Inherited from Layer

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

signal AbortSignal|null|undefined

optional

A signal to abort the creation of the layerview.

Returns

Type	Description
Promise<LayerView>	Resolves with a LayerView instance.

See also

Sample - Custom WebGL layer view

createPopupTemplate Method createPopupTemplate(options){PopupTemplate |null |undefined}

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

Notes

The ParquetLayer's popupTemplate displays only the attributes of the topmost feature when features overlap.

Parameter

options CreatePopupTemplateOptions

optional

Options for creating the popup template.

Returns

Type	Description
PopupTemplate \| null \| undefined	The popup template, or `null` if the layer does not have any fields.

destroy Inherited Method destroy() Inherited from Layer

Destroys the layer and any associated resources (including its portalItem, if it is a property on the layer). The layer can no longer be used once it has been destroyed.

The destroyed layer will be removed from its parent object like Map, WebMap, WebScene, Basemap, Ground, or GroupLayer.

See also

emit Inherited Method emit(type, event){Boolean} Inherited from Layer

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

fetchAttributionData Inherited Method fetchAttributionData(){Promise<Object>} Inherited from Layer

Fetches custom attribution data for the layer when it becomes available.

Returns

Type	Description
Promise<Object>	Resolves to an object containing custom attribution data for the layer.

getField Method getField(fieldName){Field |null |undefined}

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

Parameter

fieldName String

Name of the field.

Returns

Type	Description
Field \| null \| undefined	the matching field or `undefined`

See also

fields

getFieldDomain Method getFieldDomain(fieldName, options){Domain |null |undefined}

Returns the Domain associated with the given field name. The domain can be either a CodedValueDomain or RangeDomain.

Parameters

fieldName String

Name of the field.

options Object

optional

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

Specification

feature Graphic

The feature to which the Domain is assigned.

Returns

Type	Description
Domain \| null \| undefined	The Domain object associated with the given field name for the given feature.

hasEventListener Inherited Method hasEventListener(type){Boolean} Inherited from Layer

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 Inherited Method hasHandles(groupKey){Boolean} Inherited from Accessor

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");
}

isFulfilled Inherited Method isFulfilled(){Boolean} Inherited from Layer

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 Inherited Method isRejected(){Boolean} Inherited from Layer

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 Inherited Method isResolved(){Boolean} Inherited from Layer

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.

load Inherited Method load(options){Promise} Inherited from Layer

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.

The load() method only triggers the loading of the resource the first time it is called. The subsequent calls return the same promise.

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.

Parameters

options Object|null|undefined

optional

Additional options.

Specification

signal AbortSignal|null|undefined

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	Resolves when the resources have loaded.

on Inherited Method on(type, listener){Object} Inherited from Layer

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);
});

queryExtent Method queryExtent(query, options){Promise<Object>} Since: ArcGIS Maps SDK for JavaScript 4.34 ParquetLayer since 4.33, queryExtent added at 4.34.

Executes a Query against the ParquetLayer and returns the Extent and count of features that satisfy the query. If no parameters are specified, then the extent and count of all features satisfying the layer's configuration/filters are returned.

To query count of features available for drawing in the MapView, you must use the ParquetLayerView.queryExtent().

Parameters

query Query|null autocast

optional

Autocasts from Object

Specifies the attributes and spatial filter of the query. If no parameters are specified, then the extent and count of all features satisfying the layer's configuration/filters are returned.

options Object

optional

An object with the following properties.

Specification

signal AbortSignal|null|undefined

optional

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 \| null	The extent of the features that satisfy the query.

Examples

// Queries for the extent of all features matching the layer's configurations
// e.g. definitionExpression
layer.queryExtent().then((results) => {
  // go to the extent of the results satisfying the query
  view.goTo(results.extent);
});

const query = new Query();
query.where = "region = 'Southern California'";

const result = await layer.queryExtent(query);
view.goTo(result.extent);  // go to the extent of the results satisfying the query

queryFeatureCount Method queryFeatureCount(query, options){Promise<Number>} Since: ArcGIS Maps SDK for JavaScript 4.34 ParquetLayer since 4.33, queryFeatureCount added at 4.34.

Executes a Query against the ParquetLayer and returns the number of features that satisfy the query. If no parameters are specified, the total number of features satisfying the layer's configuration/filters is returned.

To query count of features available for drawing in the MapView, you must use the ParquetLayerView.queryFeatureCount().

Parameters

query Query|null autocast

optional

Autocasts from Object

Specifies the attributes and spatial filter of the query. If no parameters are specified, the total number of features satisfying the layer's configuration/filters is returned.

options Object

optional

An object with the following properties.

Specification

signal AbortSignal|null|undefined

optional

Returns

Type	Description
Promise<Number>	When resolved, returns the number of features that satisfy the query.

Examples

// Queries for the count of all features matching the layer's configurations
// e.g. definitionExpression
layer.queryFeatureCount().then((numFeatures) =>{
  // prints the total count to the console
  console.log(numFeatures);
});

const query = new Query();
query.where = "region = 'Southern California'";

layer.queryFeatureCount(query).then((numResults) => {
  console.log(numResults);  // prints the number of results satisfying the query
});

queryFeatures Method queryFeatures(query, options){Promise<FeatureSet>} Since: ArcGIS Maps SDK for JavaScript 4.34 ParquetLayer since 4.33, queryFeatures added at 4.34.

Executes a Query against the ParquetLayer and returns a FeatureSet once the promise resolves. A FeatureSet contains an array of Graphic features.

To query features available for drawing in the MapView, you must use the ParquetLayerView.queryFeatures().

Known Limitations

The ParquetLayer does not support the outStatistics, orderByFields, or returnDistinctValues query parameters when the layer has more than 20,000 features.
Attribute values used in attribute queries executed against ParquetLayer are case sensitive.

Parameters

query Query|null autocast

optional

Autocasts from Object

Specifies the attributes and spatial filter of the query. If no parameters are specified, then all features satisfying the layer's configuration/filters are returned.

options Object

optional

An object with the following properties.

Specification

signal AbortSignal|null|undefined

optional

Returns

Type	Description
Promise<FeatureSet>	When resolved, a FeatureSet containing an array of features is returned.

See also

Examples

// Queries for all the features matching the layer's configurations
// e.g. definitionExpression
layer.queryFeatures().then((results) => {
  // prints the array of result graphics to the console
  console.log(results.features);
});

const layer = new ParquetLayer({
  urls: [
    "parquet-file-url1.parquet"
  ]
});

const query = new Query();
query.where = "STATE_NAME = 'Washington'";
query.returnGeometry = true;
query.outFields = [ "CITY_NAME" ];

layer.queryFeatures(query).then((results) => {
  console.log(results.features);  // prints the array of features to the console
});

// Get a query object for the layer's current configuration
const queryParams = layer.createQuery();
// set a geometry for filtering features by a region of interest
queryParams.geometry = extentForRegionOfInterest;
// Add to the layer's current definitionExpression
queryParams.where = queryParams.where + " AND TYPE = 'Extreme'";

// query the layer with the modified params object
layer.queryFeatures(queryParams).then((results) => {
  // prints the array of result graphics to the console
  console.log(results.features);
});

layer.queryFeatures(query).then((results) => {
  console.log(results.features);  // prints the array of features to the console
});

queryObjectIds Method queryObjectIds(query, options){Promise<Array<(number|string)>>} Since: ArcGIS Maps SDK for JavaScript 4.34 ParquetLayer since 4.33, queryObjectIds added at 4.34.

Executes a Query against the ParquetLayer and returns an array of Object IDs for features that satisfy the input query. If no parameters are specified, then the Object IDs of all features satisfying the layer's configuration/filters are returned.

To query ObjectIDs of features available for drawing in the MapView, you must use the ParquetLayerView.queryObjectIds().

Parameters

query Query|null autocast

optional

Autocasts from Object

Specifies the attributes and spatial filter of the query. If no parameters are specified, then the Object IDs of all features satisfying the layer's configuration/filters are returned.

options Object

optional

An object with the following properties.

Specification

signal AbortSignal|null|undefined

optional

Returns

Type	Description
Promise<Array<(number\|string)>>	When resolved, returns an array of numbers representing the object IDs of the features satisfying the query.

Examples

// Queries for all the Object IDs of features matching the layer's configurations
// e.g. definitionExpression
layer.queryObjectIds().then((results) =>{
  // prints the array of Object IDs to the console
  console.log(results);
});

const query = new Query({
  where: "SUB_REGION = 'Pacific'"
});

const ids = await parquetLayer.queryObjectIds(query);
console.log(ids);  // an array of object IDs

removeHandles Inherited Method removeHandles(groupKey) Inherited from Accessor

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");

when Inherited Method when(onFulfilled, onRejected){Promise} Inherited from Layer

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

Parameters

onFulfilled Function

optional

The function to call when the promise resolves.

onRejected Function

optional

The function to execute when the promise fails.

Returns

Type	Description
Promise	Returns a new promise for the result of `onFulfilled` 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

Show inherited events

Hide inherited events

Type	Summary	Class
{view: View,layerView: LayerView}	Fires after the layer's LayerView is created and rendered in a view.	Layer
{view: View,error: Error}	Fires when an error emits during the creation of a LayerView after a layer has been added to the map.	Layer
{view: View,layerView: LayerView}	Fires after the layer's LayerView is destroyed and no longer renders in a view.	Layer

Event Details

layerview-create Inherited Event layerview-create Inherited from Layer

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

View.whenLayerView()

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-error Inherited Event layerview-create-error Inherited from Layer

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

View.whenLayerView()

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-destroy Inherited Event layerview-destroy Inherited from Layer

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.