| interface CompletionPollOptions<T> { | |
| delayMs: number | |
| poll: () => Promise<T> | |
| publish: (value: T) => void | |
| } | |
| /** | |
| * Poll immediately, then wait one full cadence AFTER each request settles. | |
| * | |
| * `setInterval` fires on the wall clock, so a request slower than the cadence | |
| * overlaps the next one and a stalled backend piles up concurrent requests. | |
| * Rescheduling from settlement keeps the poll single-flight. The returned stop | |
| * function drops the pending timer and suppresses a late publish. | |
| */ | |
| export function startCompletionPoll<T>({ delayMs, poll, publish }: CompletionPollOptions<T>): () => void { | |
| let stopped = false | |
| let timer: number | undefined | |
| const run = async () => { | |
| try { | |
| const value = await poll() | |
| if (!stopped) { | |
| publish(value) | |
| } | |
| } catch { | |
| // A transient producer failure keeps the previous value visible. | |
| } | |
| if (!stopped) { | |
| timer = window.setTimeout(() => void run(), delayMs) | |
| } | |
| } | |
| void run() | |
| return () => { | |
| stopped = true | |
| window.clearTimeout(timer) | |
| } | |
| } | |