diff --git a/assets/ts/container.ts b/assets/ts/container.ts
index 8dd3c99..63fd864 100644
--- a/assets/ts/container.ts
+++ b/assets/ts/container.ts
@@ -4,8 +4,8 @@ export let container: HTMLDivElement
 
 export function initContainer(): void {
   container = document.getElementsByClassName('container').item(0) as HTMLDivElement
-  scrollable.addWatcher(() => {
-    if (scrollable.get()) {
+  scrollable.addWatcher((o) => {
+    if (o) {
       container.classList.remove('disableScroll')
     } else {
       container.classList.add('disableScroll')
diff --git a/assets/ts/desktop/customCursor.ts b/assets/ts/desktop/customCursor.ts
index 5476a35..6b1bf4d 100644
--- a/assets/ts/desktop/customCursor.ts
+++ b/assets/ts/desktop/customCursor.ts
@@ -38,8 +38,8 @@ export function initCustomCursor(): void {
   // bind mousemove event to window
   window.addEventListener('mousemove', onMouse, { passive: true })
   // add active callback
-  active.addWatcher(() => {
-    if (active.get()) {
+  active.addWatcher((o) => {
+    if (o) {
       cursor.classList.add('active')
     } else {
       cursor.classList.remove('active')
diff --git a/assets/ts/desktop/stage.ts b/assets/ts/desktop/stage.ts
index 04a0eb3..eb73eb7 100644
--- a/assets/ts/desktop/stage.ts
+++ b/assets/ts/desktop/stage.ts
@@ -211,13 +211,13 @@ export function initStage(ijs: ImageJSON[]): void {
   })
   window.addEventListener('mousemove', onMouse, { passive: true })
   // watchers
-  isOpen.addWatcher(() => {
-    active.set(isOpen.get() && !isAnimating.get())
+  isOpen.addWatcher((o) => {
+    active.set(o && !isAnimating.get())
   })
-  isAnimating.addWatcher(() => {
-    active.set(isOpen.get() && !isAnimating.get())
+  isAnimating.addWatcher((o) => {
+    active.set(isOpen.get() && !o)
   })
-  cordHist.addWatcher(() => {
+  cordHist.addWatcher((_) => {
     setPositions()
   })
   // preload
diff --git a/assets/ts/mobile/gallery.ts b/assets/ts/mobile/gallery.ts
index a042d45..9b36174 100644
--- a/assets/ts/mobile/gallery.ts
+++ b/assets/ts/mobile/gallery.ts
@@ -93,8 +93,8 @@ export function initGallery(ijs: ImageJSON[]): void {
     lastIndex = s.index
   })
   // mounted watcher
-  mounted.addWatcher(() => {
-    if (!mounted.get()) return
+  mounted.addWatcher((o) => {
+    if (!o) return
     scrollable.set(true)
     swiper = new Swiper(swiperNode, { spaceBetween: 20 })
     swiper.on('slideChange', ({ realIndex }) => {
diff --git a/assets/ts/utils.ts b/assets/ts/utils.ts
index 751a3c0..9cdfef3 100644
--- a/assets/ts/utils.ts
+++ b/assets/ts/utils.ts
@@ -42,7 +42,7 @@ export function onVisible<T extends Element>(
 
 export class Watchable<T> {
   constructor(private obj: T) {}
-  private readonly watchers: Array<() => void> = []
+  private readonly watchers: Array<(arg0: T) => void> = []
 
   get(): T {
     return this.obj
@@ -51,11 +51,11 @@ export class Watchable<T> {
   set(e: T): void {
     this.obj = e
     this.watchers.forEach((watcher) => {
-      watcher()
+      watcher(this.obj)
     })
   }
 
-  addWatcher(watcher: () => void): void {
+  addWatcher(watcher: (arg0: T) => void): void {
     this.watchers.push(watcher)
   }
 }