refactor: convert to ECMAScript where necessary

Also drop @league-of-foundry-developers/foundry-vtt-types.

src/migration/002.js

@@ -0,0 +1,40 @@
+// SPDX-FileCopyrightText: 2021 Johannes Loher
+//
+// SPDX-License-Identifier: MIT
+
+import {
+    getActorUpdateDataGetter,
+    getCompendiumMigrator,
+    getSceneUpdateDataGetter,
+    migrateActors,
+    migrateCompendiums,
+    migrateItems,
+    migrateScenes,
+} from "./migrationHelpers";
+
+/** @type {import("./migration").Migration["migrate"]} */
+async function migrate() {
+    await migrateItems(getItemUpdateData);
+    await migrateActors(getActorUpdateData);
+    await migrateScenes(getSceneUpdateData);
+    await migrateCompendiums(migrateCompendium);
+}
+
+/** @type {import("./migrationHelpers").ItemUpdateDataGetter} */
+function getItemUpdateData(itemData) {
+    if (!["equipment", "trinket"].includes(itemData.type ?? "")) return undefined;
+    return { type: itemData.type === "equipment" ? "loot" : "equipment" };
+}
+
+const getActorUpdateData = getActorUpdateDataGetter(getItemUpdateData);
+const getSceneUpdateData = getSceneUpdateDataGetter(getActorUpdateData);
+const migrateCompendium = getCompendiumMigrator(
+    { getItemUpdateData, getActorUpdateData, getSceneUpdateData },
+    { migrateToTemplateEarly: false },
+);
+
+/** @type {import("./migration").Migration} */
+export const migration = {
+    migrate,
+    migrateCompendium,
+};