refactor: use events for control-layers layer add/remove instead of DOM traversal

Replace the #map getter (which used closest("leaflet-map") + leafletObject)
with two new custom events: leaflet-add-layer and leaflet-remove-layer.
The map listens for them and delegates to map.addLayer/removeLayer.

This removes the coupling between leaflet-control-layers and the map
element, aligning with the existing leaflet-register event protocol.

src/components/leaflet-control-layers.ts

@@ -25,8 +25,11 @@ export class LeafletControlLayers extends WithProps(HTMLElement, PROPS) {
       if (!checked) uncheckedLayers.push(layer);
     }
 
-    const map = this.#map;
-    for (const layer of uncheckedLayers) map?.removeLayer(layer);
+    for (const layer of uncheckedLayers) {
+      this.dispatchEvent(
+        new CustomEvent('leaflet-remove-layer', { bubbles: true, detail: { layer } }),
+      );
+    }
 
     this.#obj = new Control.Layers(baseLayers, overlays, {
       position: this.getAttribute('position') as ControlPosition | undefined,
@@ -57,24 +60,6 @@ export class LeafletControlLayers extends WithProps(HTMLElement, PROPS) {
     return this.#obj;
   }
 
-  get #map():
-    | {
-        removeLayer(l: Layer): unknown;
-        addLayer(l: Layer): unknown;
-      }
-    | undefined {
-    const mapEl = this.closest('leaflet-map');
-    if (!mapEl) return undefined;
-    return (
-      mapEl as unknown as {
-        leafletObject?: {
-          removeLayer(l: Layer): unknown;
-          addLayer(l: Layer): unknown;
-        };
-      }
-    ).leafletObject;
-  }
-
   #onChildRegister = (e: LeafletRegisterEvent) => {
     e.stopPropagation();
     const el = e.detail.element;
@@ -85,7 +70,11 @@ export class LeafletControlLayers extends WithProps(HTMLElement, PROPS) {
     const checked = el.hasAttribute('checked');
     if (base) this.#obj!.addBaseLayer(layer, name);
     else this.#obj!.addOverlay(layer, name);
-    if (checked) this.#map?.addLayer(layer);
+    if (checked) {
+      this.dispatchEvent(
+        new CustomEvent('leaflet-add-layer', { bubbles: true, detail: { layer } }),
+      );
+    }
   };
 }
 

src/components/leaflet-map.ts

@@ -1,4 +1,4 @@
-import { Icon, Map as LMap, MapOptions } from 'leaflet';
+import { Icon, Layer, Map as LMap, MapOptions } from 'leaflet';
 import { defineProps, num, off, on, type NumProp, type PropDef } from '../core/props.ts';
 import { LeafletRegisterEvent } from '../core/register.ts';
 
@@ -205,6 +205,8 @@ export class LeafletMap extends TypedBase {
       'leaflet-register',
       this.#handleLeafletRegister as EventListenerOrEventListenerObject,
     );
+    this.addEventListener('leaflet-add-layer', this.#onAddLayer);
+    this.addEventListener('leaflet-remove-layer', this.#onRemoveLayer);
   }
 
   disconnectedCallback() {
@@ -214,6 +216,8 @@ export class LeafletMap extends TypedBase {
       'leaflet-register',
       this.#handleLeafletRegister as EventListenerOrEventListenerObject,
     );
+    this.removeEventListener('leaflet-add-layer', this.#onAddLayer);
+    this.removeEventListener('leaflet-remove-layer', this.#onRemoveLayer);
     if (!this.#map) return;
     for (const [event, handler] of this.#mapEventHandlers) {
       this.#map.off(event, handler);
@@ -309,6 +313,14 @@ export class LeafletMap extends TypedBase {
     }
   };
 
+  #onAddLayer = (e: Event) => {
+    this.#map?.addLayer((e as CustomEvent<{ layer: Layer }>).detail.layer);
+  };
+
+  #onRemoveLayer = (e: Event) => {
+    this.#map?.removeLayer((e as CustomEvent<{ layer: Layer }>).detail.layer);
+  };
+
   get leafletObject() {
     return this.#map;
   }

src/core/register.ts

@@ -9,9 +9,13 @@ export type LeafletRegisterEvent = CustomEvent<{
   element: HTMLElement;
 }>;
 
+export type LeafletLayerEvent = CustomEvent<{ layer: Layer }>;
+
 declare global {
   interface HTMLElementEventMap {
     'leaflet-register': LeafletRegisterEvent;
+    'leaflet-add-layer': LeafletLayerEvent;
+    'leaflet-remove-layer': LeafletLayerEvent;
   }
 }