@ulm/maplibre

new MapLibreLayerManagerAdapter<TLayer, TGroup>(map, options?)

A LayerManagerAdapter for MapLibre GL JS. Attach it with manager.setAdapter(adapter). TLayer is your layer data type and TGroup your group data type, which defaults to undefined. See the MapLibre guide for how it shows, stacks and fades layers.

Options (all optional):

Option	Type	Description
renderLayer	(info, map, current?) => MapLibreLayerStyle | null	Returns the sources and style layers to show for a layer, or null to leave it off the map. Called when a layer is added, and again when its layerData or timeInfo changes, with the style it returned last time as current. Return current to leave the map as it is. Defaults to defaultMapLibreRenderLayer. Required unless the layer data is a MapLibreLayerStyle
disposeLayer	(style, layerId) => void	Called with a style renderLayer returned, once the adapter discards it: when its layer is removed, when renderLayer returns a different style, and when the adapter is detached. Not called when a layer is hidden, or when a style differs only in GeoJSON data or tile URLs, which MapLibre updates in place
drawBelow	string	The ID of a basemap style layer to draw every layer below. Without it, or while the map lacks that layer, layers draw below the first symbol layer with text, or on top when there is none

LayerManager calls the adapter's methods as layers change, so you don't call them yourself. The adapter waits for the map's style to load before it shows anything, and shows the layers again after map.setStyle. When the adapter is detached, replaced, or the manager is destroyed, it removes every source and style layer it added from the map.

Sources and style layers keep the IDs renderLayer gives them. If the map already has one of a layer's IDs from elsewhere, such as the basemap, the adapter leaves that layer off the map and fires a MapLibre error event.

defaultMapLibreRenderLayer(info)

The default renderLayer: it returns layerData as the layer's style when it is a MapLibreLayerStyle and otherwise null. Call it from your own renderLayer for the layers you don't handle.

Types

Type	Description
MapLibreLayerStyle	{ sources?, layers }: the sources a layer reads, by ID, and its style layers, bottom first. Layers that list the same source share it
MapLibreRenderLayer<TLayer>	The type of the renderLayer option: RenderLayer<TLayer, MapLibreMap, MapLibreLayerStyle> from @ulm/core
MapLibreAdapterOptions<TLayer>	The adapter's options: RenderAdapterOptions from @ulm/core, plus drawBelow
StyleSpecification, LayerSpecification, SourceSpecification	MapLibre's style, style layer and source types, which maplibre-gl itself does not export