add special creature ability as item type

src/module/actor/actor.ts

@@ -1,6 +1,7 @@
+import { ModifiableData } from "../common/common-data";
 import { DS4Item } from "../item/item";
-import { DS4ItemDataType } from "../item/item-data";
-import { DS4ActorDataType, ModifiableData } from "./actor-data";
+import { DS4ItemDataType, ItemType } from "../item/item-data";
+import { DS4ActorDataType } from "./actor-data";
 
 export class DS4Actor extends Actor<DS4ActorDataType, DS4ItemDataType, DS4Item> {
     /** @override */
@@ -21,4 +22,37 @@ export class DS4Actor extends Actor<DS4ActorDataType, DS4ItemDataType, DS4Item>
 
         combatValues.hitPoints.max = combatValues.hitPoints.total;
     }
+
+    /**
+     * The list of item types that can be owned by this actor.
+     */
+    get ownableItemTypes(): Array<ItemType> {
+        switch (this.data.type) {
+            case "character":
+                return [
+                    "weapon",
+                    "armor",
+                    "shield",
+                    "spell",
+                    "trinket",
+                    "equipment",
+                    "talent",
+                    "racialAbility",
+                    "language",
+                    "alphabet",
+                ];
+            case "creature":
+                return ["weapon", "armor", "spell", "specialCreatureAbility"];
+            default:
+                [];
+        }
+    }
+
+    /**
+     * Checks whether or not the given item type can be owned by the actor.
+     * @param itemType the item type to check
+     */
+    canOwnItemType(itemType: ItemType): boolean {
+        return this.ownableItemTypes.includes(itemType);
+    }
 }