fix(useDevicePixelRatio): remove unnecessary cleanup (#2325)

Co-authored-by: Anthony Fu <anthonyfu117@hotmail.com>

packages/core/useDevicePixelRatio/index.ts

@@ -1,5 +1,5 @@
 import { ref } from 'vue-demi'
-import { type Fn, tryOnScopeDispose } from '@vueuse/shared'
+import { tryOnScopeDispose } from '@vueuse/shared'
 import { type ConfigurableWindow, defaultWindow } from '../_configurable'
 
 /**
@@ -11,34 +11,24 @@ import { type ConfigurableWindow, defaultWindow } from '../_configurable'
 export function useDevicePixelRatio({
   window = defaultWindow,
 }: ConfigurableWindow = {}) {
-  if (!window) {
-    return {
-      pixelRatio: ref(1),
-    }
-  }
-
   const pixelRatio = ref(1)
 
-  const cleanups: Fn[] = []
-
-  const cleanup = () => {
-    cleanups.map(i => i())
-    cleanups.length = 0
-  }
+  if (window) {
+    let media: MediaQueryList
+    function observe() {
+      pixelRatio.value = window!.devicePixelRatio
+      cleanup()
+      media = window!.matchMedia(`(resolution: ${pixelRatio.value}dppx)`)
+      media.addEventListener('change', observe, { once: true })
+    }
+    function cleanup() {
+      media?.removeEventListener('change', observe)
+    }
 
-  const observe = () => {
-    pixelRatio.value = window.devicePixelRatio
-    cleanup()
-    const media = window.matchMedia(`(resolution: ${pixelRatio.value}dppx)`)
-    media.addEventListener('change', observe, { once: true })
-    cleanups.push(() => {
-      media.removeEventListener('change', observe)
-    })
+    observe()
+    tryOnScopeDispose(cleanup)
   }
 
-  observe()
-  tryOnScopeDispose(cleanup)
-
   return { pixelRatio }
 }