feat(useWindowScroll): allow rewriting back to scroll

packages/core/useWindowScroll/demo.vue

@@ -1,7 +1,7 @@
 <script setup lang="ts">
 import { useWindowScroll } from '@vueuse/core'
 
-const { x, y } = useWindowScroll()
+const { x, y } = useWindowScroll({ behavior: 'smooth' })
 </script>
 
 <template>
@@ -18,6 +18,12 @@ const { x, y } = useWindowScroll()
       y: {{ y }}
     </div>
   </div>
+  <button @click="x += 200">
+    scroll X
+  </button>
+  <button @click="y += 200">
+    scroll Y
+  </button>
 </template>
 
 <style scoped>

packages/core/useWindowScroll/index.md

@@ -12,4 +12,6 @@ Reactive window scroll
 import { useWindowScroll } from '@vueuse/core'
 
 const { x, y } = useWindowScroll()
+x.value = 100
+y.value = 100
 ```

packages/core/useWindowScroll/index.ts

@@ -1,32 +1,54 @@
-import { ref } from 'vue-demi'
+import { computed, ref } from 'vue-demi'
 import { useEventListener } from '../useEventListener'
 import type { ConfigurableWindow } from '../_configurable'
 import { defaultWindow } from '../_configurable'
 
+export interface UseWindowScrollOptions extends ConfigurableWindow {
+  behavior?: ScrollBehavior
+}
+
 /**
  * Reactive window scroll.
  *
  * @see https://vueuse.org/useWindowScroll
  * @param options
  */
-export function useWindowScroll(options: ConfigurableWindow = {}) {
-  const { window = defaultWindow } = options
+
+export function useWindowScroll(options: UseWindowScrollOptions = {}) {
+  const { window = defaultWindow, behavior = 'auto' } = options
   if (!window) {
     return {
       x: ref(0),
       y: ref(0),
     }
   }
 
-  const x = ref(window.scrollX)
-  const y = ref(window.scrollY)
+  const internalX = ref(window.scrollX)
+  const internalY = ref(window.scrollY)
+
+  const x = computed({
+    get() {
+      return internalX.value
+    },
+    set(x: number) {
+      scrollTo({ left: x, behavior })
+    },
+  })
+  const y = computed({
+    get() {
+      return internalY.value
+    },
+    set(y: number) {
+      scrollTo({ top: y, behavior })
+    },
+  })
 
   useEventListener(
     window,
     'scroll',
     () => {
-      x.value = window.scrollX
-      y.value = window.scrollY
+      internalX.value = window.scrollX
+      internalY.value = window.scrollY
     },
     {
       capture: false,