Improve application responsiveness and background processing

src/lib/ui/poll.ts

@@ -1,25 +1,32 @@
 /** Poll visible page content without overlapping requests. Fleet watches use their own monitor. */
-export function pollVisible(task: () => void | Promise<unknown>, interval: number, immediate = true): () => void {
+export function pollVisible(task: (signal: AbortSignal) => unknown | Promise<unknown>, interval: number, immediate = true): () => void {
     let stopped = false;
     let running = false;
     let timer: ReturnType<typeof setTimeout> | undefined;
+    let controller: AbortController | undefined;
+    let failures = 0;
     const visible = () => document.visibilityState !== 'hidden';
     const run = async () => {
         if (stopped || running || !visible()) return;
         clearTimeout(timer);
         running = true;
-        try { await task(); }
-        catch (error) { console.error('Page refresh failed', error); }
+        controller = new AbortController();
+        const timeout = setTimeout(() => controller?.abort(), 30_000);
+        try { failures = await task(controller.signal) === false ? failures + 1 : 0; }
+        catch (error) { if (!controller.signal.aborted) { failures++; console.error('Page refresh failed', error); } }
         finally {
+            clearTimeout(timeout);
+            controller = undefined;
             running = false;
-            if (!stopped && visible()) timer = setTimeout(run, interval);
+            if (!stopped && visible()) timer = setTimeout(run, interval * Math.min(8, 2 ** failures));
         }
     };
     const visibility = () => {
         clearTimeout(timer);
+        if (!visible()) controller?.abort();
         if (document.visibilityState !== 'hidden') void run();
     };
     document.addEventListener('visibilitychange', visibility);
     if (immediate) void run(); else timer = setTimeout(run, interval);
-    return () => { stopped = true; clearTimeout(timer); document.removeEventListener('visibilitychange', visibility); };
+    return () => { stopped = true; clearTimeout(timer); controller?.abort(); document.removeEventListener('visibilitychange', visibility); };
 }