move composables to their own folder

src/composables/useScrollPosition.js

@@ -0,0 +1,21 @@
+import { onMounted, onUnmounted, ref } from 'vue'
+
+export function useScrollPosition() {
+  const x = ref(0)
+  const y = ref(0)
+
+  const update = (e) => {
+    x.value = window.scrollX
+    y.value = window.scrollY
+  }
+
+  onMounted(() => {
+    window.addEventListener('scroll', update)
+    update()
+  })
+  onUnmounted(() => {
+    window.removeEventListener('scroll', update)
+  })
+
+  return { x, y }
+}

src/composables/useWindowSize.js

@@ -0,0 +1,18 @@
+import { onMounted, onUnmounted, ref } from 'vue'
+
+export function useWindowSize() {
+  const height = ref(0)
+  const width = ref(0)
+
+  const update = () => {
+    height.value = window.innerHeight
+    width.value = window.innerWidth
+  }
+
+  onMounted(() => window.addEventListener('resize', update))
+  onUnmounted(() => window.removeEventListener('resize', update))
+
+  update()
+
+  return { height, width }
+}