feat(polling): Avoid redundant polling before ETA

app.py

@@ -113,6 +113,7 @@ def create_task(background_tasks: BackgroundTasks, new_task: NewTask):
     }
 
     tasks[task_id]["initial_place_in_queue"] = get_place_in_queue(task_id)
+    tasks[task_id]["eta"] = calculate_eta(task_id)
 
     background_tasks.add_task(process_task, task_id)
 

static/js/index.js

@@ -41,7 +41,10 @@ const generate = async () => {
     const timer = durationTimer(durationDisplay);
     const timerCleanup = timer().cleanup;
 
-    const completedTask = await longPollTask(task);
+    // Theoretically, keep client waiting only an extra half interval once task is complete
+    const interval = 5_000;
+    await new Promise((resolve) => setTimeout(resolve, task.eta * 1_000 - interval / 2));
+    const completedTask = await longPollTask(task, interval);
 
     generating = false;
     timerCleanup(completedTask);