Highlight

Overview

useHighlight(name, options) manages a reactive store of map highlights — styled GeoJSON features rendered on top of the map to indicate selection or focus. It maintains a dedicated system GeoJSON layer (HighlightsLayerName) and keeps highlights in sync with real-time service events on feature layers.

Highlights are debounced (configurable via options.updateDelay) and rendered sorted by zOrder from the properties.

Usage

import { useHighlight } from '@kalisio/kdk/map.client'

const {
  highlights, highlight, unhighlight,
  hasHighlight, getHighlight, clearHighlights
} = useHighlight('myMap', { updateDelay: 100, asBbox: false })

Parameters

Parameter	Type	Default	Description
name	string	—	Unique highlight store name within the application. Used as the key in the highlights namespace of the global store.
options.updateDelay	number	250	Debounce delay in milliseconds for updating the highlights layer.
options.asBbox	boolean	false	When true, lines and polygons are highlighted using their bounding box polygon instead of the original geometry.
(map style properties)	—	—	Any additional style properties are merged into each highlight feature as default style overrides.

Exposed

Name	Type	Description
highlights	reactive Object	The raw highlight store for this name. Keys are highlight IDs, values are highlight feature objects.
setCurrentActivity(activity)	Function	Binds the composable to a new map activity instance. Removes the highlights layer from the previous activity and registers it on the new one.
setHighlightMode(mode)	Function	Sets the highlight filtering mode. 'highlightable-layers' (default) only highlights features from layers where isHighlightable is true. Any other string disables this filter.
hasHighlight(feature, layer)	Function	Returns true if a highlight exists for the given feature and layer.
getHighlight(feature, layer)	Function	Returns the highlight object for the given feature and layer, or undefined.
getHighlights(layer?, feature?)	Function	Returns all current highlights. Optionally filtered by layer and/or feature. Aggregates across all highlight stores (all names).
highlight(feature, layer, selected?)	Function	Adds or updates a highlight for the given feature. When selected is true (default), applies the engine selection style; otherwise uses the feature's own style. Returns the highlight object.
unhighlight(feature, layer)	Function	Removes the highlight for the given feature and layer.
setHighlightEnabled(feature, layer, enabled?)	Function	Shows or hides a single highlight by setting its style.visibility.
setHighlightsEnabled(layer, enabled?)	Function	Shows or hides all highlights associated with a given layer.
clearHighlights()	Function	Removes all highlights from the store and updates the layer.

Constants

Name	Description
HighlightsLayerName	Unique name of the system GeoJSON layer used to render highlights. Generated with uid().
HighlightsZIndex	Z-index (999) of the highlights layer, ensuring it renders on top of all other layers.
HighlightMargin	Extra pixels (8) added to a highlight marker's radius/size to visually encompass the target feature.

Lifecycle

• beforeMount: Starts listening to feature service events on all existing layers.
• beforeUnmount: Stops listening to feature service events and clears all highlights.
• Registers layer-added / layer-removed handlers to track real-time events per layer.
• Registers layer-disabled / layer-enabled handlers to toggle highlight visibility.
• The highlights layer is created automatically when the first catalog layer is added to the activity, and removed when the activity changes.