refactor: convert to ECMAScript where necessary

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

src/apps/active-effect-config.js

@@ -0,0 +1,38 @@
+// SPDX-FileCopyrightText: 2022 Johannes Loher
+//
+// SPDX-License-Identifier: MIT
+
+export class DS4ActiveEffectConfig extends ActiveEffectConfig {
+    /** @override */
+    static get defaultOptions() {
+        return foundry.utils.mergeObject(super.defaultOptions, {
+            template: "systems/ds4/templates/sheets/active-effect/active-effect-config.hbs",
+        });
+    }
+
+    /**
+     * @override
+     * @param {JQuery} html
+     */
+    activateListeners(html) {
+        super.activateListeners(html);
+        const checkbox = html[0]?.querySelector('input[name="flags.ds4.itemEffectConfig.applyToItems"]');
+        checkbox?.addEventListener("change", () => this.#toggleItemEffectConfig(checkbox.checked));
+    }
+
+    /**
+     * Toggle the visibility of the item effect config section
+     * @param {boolean} active The target state
+     */
+    #toggleItemEffectConfig(active) {
+        const elements = this.element[0]?.querySelectorAll(".ds4-item-effect-config");
+        elements?.forEach((element) => {
+            if (active) {
+                element.classList.remove("ds4-hidden");
+            } else {
+                element.classList.add("ds4-hidden");
+            }
+        });
+        this.setPosition({ height: "auto" });
+    }
+}