feat: following and followers routes (#4)

composables/paginator.ts

@@ -0,0 +1,41 @@
+import type { Paginator } from 'masto'
+
+export function usePaginator<T>(paginator: Paginator<any, T[]>) {
+  let isLoading = $ref(false)
+  let isDone = $ref(false)
+  const items = $ref<T[]>([])
+
+  const endAnchor = ref<HTMLDivElement>()
+  const bound = reactive(useElementBounding(endAnchor))
+  const isInScreen = $computed(() => bound.top < window.innerHeight * 2)
+
+  async function loadNext() {
+    if (isLoading || isDone)
+      return
+
+    isLoading = true
+    const result = await paginator.next()
+    if (result.done)
+      isDone = true
+    if (result.value?.length)
+      items.push(...result.value)
+    isLoading = false
+    await nextTick()
+    bound.update()
+  }
+
+  useIntervalFn(() => {
+    bound.update()
+  }, 1000)
+
+  watch(
+    () => isInScreen,
+    () => {
+      if (isInScreen && !isLoading)
+        loadNext()
+    },
+    { immediate: true },
+  )
+
+  return { items, isLoading, isDone, endAnchor }
+}