Merge pull request #13902 from MoonE/type-safe-collection

Improve Collection type-safety

src/ol/layer/Group.js

@@ -66,7 +66,7 @@ export class GroupEvent extends Event {
  * visible.
  * @property {number} [maxZoom] The maximum view zoom level (inclusive) at which this layer will
  * be visible.
- * @property {Array<import("./Base.js").default>|import("../Collection.js").default<import("./Base.js").default>} [layers] Child layers.
+ * @property {Array<import("./Base.js").default>|Collection<import("./Base.js").default>} [layers] Child layers.
  * @property {Object<string, *>} [properties] Arbitrary observable properties. Can be accessed with `#get()` and `#set()`.
  */
 
@@ -214,26 +214,22 @@ class LayerGroup extends BaseLayer {
   }
 
   /**
-   * @param {import("../Collection.js").CollectionEvent} collectionEvent CollectionEvent.
+   * @param {import("../Collection.js").CollectionEvent<import("./Base.js").default>} collectionEvent CollectionEvent.
    * @private
    */
   handleLayersAdd_(collectionEvent) {
-    const layer = /** @type {import("./Base.js").default} */ (
-      collectionEvent.element
-    );
+    const layer = collectionEvent.element;
     this.registerLayerListeners_(layer);
     this.dispatchEvent(new GroupEvent('addlayer', layer));
     this.changed();
   }
 
   /**
-   * @param {import("../Collection.js").CollectionEvent} collectionEvent CollectionEvent.
+   * @param {import("../Collection.js").CollectionEvent<import("./Base.js").default>} collectionEvent CollectionEvent.
    * @private
    */
   handleLayersRemove_(collectionEvent) {
-    const layer = /** @type {import("./Base.js").default} */ (
-      collectionEvent.element
-    );
+    const layer = collectionEvent.element;
     const key = getUid(layer);
     this.listenerKeys_[key].forEach(unlistenByKey);
     delete this.listenerKeys_[key];
@@ -244,13 +240,13 @@ class LayerGroup extends BaseLayer {
   /**
    * Returns the {@link module:ol/Collection~Collection collection} of {@link module:ol/layer/Layer~Layer layers}
    * in this group.
-   * @return {!import("../Collection.js").default<import("./Base.js").default>} Collection of
+   * @return {!Collection<import("./Base.js").default>} Collection of
    *   {@link module:ol/layer/Base~BaseLayer layers} that are part of this group.
    * @observable
    * @api
    */
   getLayers() {
-    return /** @type {!import("../Collection.js").default<import("./Base.js").default>} */ (
+    return /** @type {!Collection<import("./Base.js").default>} */ (
       this.get(Property.LAYERS)
     );
   }
@@ -258,7 +254,7 @@ class LayerGroup extends BaseLayer {
   /**
    * Set the {@link module:ol/Collection~Collection collection} of {@link module:ol/layer/Layer~Layer layers}
    * in this group.
-   * @param {!import("../Collection.js").default<import("./Base.js").default>} layers Collection of
+   * @param {!Collection<import("./Base.js").default>} layers Collection of
    *   {@link module:ol/layer/Base~BaseLayer layers} that are part of this group.
    * @observable
    * @api