Work on creating more of the necessary data models

module/documents/Item/Handler.mjs

@@ -1,13 +1,11 @@
 import AspectItem from "./Aspect.mjs";
+import SpellItem from "./Spell.mjs";
 
-/**
- * @extends {Item}
- */
+/** @extends {Item} */
 export class ItemHandler extends Item {
-	/** @override */
-
 	proxyTargets = {
 		aspect: AspectItem,
+		spell: SpellItem
 	};
 
 	constructor(data, ctx) {
@@ -19,6 +17,11 @@ export class ItemHandler extends Item {
 		return this.proxyTargets[this.type];
 	};
 
+	async migrateSystemData() {
+		if (!this.fn?.migrateSystemData) return;
+		this.fn?.migrateSystemData.bind(this)();
+	};
+
 	async proxyFunction(funcName, ...args) {
 		if (!this.fn?.[funcName]) return;
 		return await this.fn?.[funcName].bind(this)(...args);

module/documents/Item/Spell.mjs

@@ -0,0 +1,10 @@
+import { ItemHandler } from "./Handler.mjs";
+
+/** @this {ItemHandler} */
+async function migrateSystemData() {
+	this.system
+};
+
+export default {
+	migrateSystemData,
+};