fix: 补齐轮询组合式函数

src/composables/usePolling.ts

@@ -0,0 +1,81 @@
+import { onScopeDispose, ref, toValue, watch, type MaybeRefOrGetter, type Ref } from 'vue'
+import { errorMessage } from '../lib/http'
+
+/** 串行轮询：请求完成后才计时；切换项目立即取消，过期响应不会覆盖新项目。 */
+export function usePolling<T>(
+    key: Ref<string>,
+    loader: (key: string, signal: AbortSignal) => Promise<T>,
+    interval: MaybeRefOrGetter<number | false> = 6000
+) {
+    const data = ref<T | null>(null) as Ref<T | null>
+    const loading = ref(false)
+    const error = ref('')
+    const updatedAt = ref('')
+    let generation = 0
+    let controller: AbortController | undefined
+    let timer: ReturnType<typeof setTimeout> | undefined
+    let disposed = false
+
+    /** 隐藏页面只安排下一次检查，不继续拉取完整 checkpoint。 */
+    function schedule() {
+        const delay = toValue(interval)
+        if (disposed || delay === false) return
+        timer = setTimeout(() => {
+            if (toValue(interval) === false) return
+            if (document.visibilityState === 'hidden') schedule()
+            else void refresh()
+        }, delay)
+    }
+
+    /** 手动刷新也取消上一次查询，避免同时存在多个轮询链。 */
+    async function refresh() {
+        if (disposed) return
+        const current = ++generation
+        clearTimeout(timer)
+        controller?.abort()
+        controller = new AbortController()
+        const signal = controller.signal
+        loading.value = true
+        try {
+            const result = await loader(key.value, signal)
+            if (current !== generation || disposed) return
+            data.value = result
+            error.value = ''
+            updatedAt.value = new Date().toISOString()
+        } catch (cause) {
+            if (current === generation && !signal.aborted && !disposed) error.value = errorMessage(cause)
+        } finally {
+            if (current === generation && !disposed) {
+                loading.value = false
+                schedule()
+            }
+        }
+    }
+
+    // 页面可关闭定时刷新；首次读取、切换查询目标和手动刷新仍然有效。
+    watch(
+        () => toValue(interval),
+        () => {
+            clearTimeout(timer)
+            if (!loading.value) schedule()
+        }
+    )
+    watch(
+        key,
+        () => {
+            data.value = null
+            error.value = ''
+            updatedAt.value = ''
+            void refresh()
+        },
+        { immediate: true }
+    )
+    onScopeDispose(() => {
+        disposed = true
+        generation++
+        clearTimeout(timer)
+        controller?.abort()
+    })
+    return { data, loading, error, updatedAt, refresh }
+}
+