export interface PollResult<T> {
success: boolean;
value: T;
attempts: number;
elapsedMs: number;
reason: 'condition_met' | 'timeout' | 'error';
error?: string;
}
export interface PollOptions {
intervalMs?: number;
maxDurationMs?: number;
onProgress?: (attempt: number, elapsed: number) => void;
}
async function sleep(ms: number): Promise<void> {
await new Promise((resolve) => setTimeout(resolve, ms));
}
export async function poll<T>(
fetcher: () => Promise<T>,
condition: (value: T) => boolean,
options: PollOptions = {},
): Promise<PollResult<T>> {
const intervalMs = options.intervalMs ?? 5000;
const maxDurationMs = options.maxDurationMs ?? 600000;
const startTime = Date.now();
let attempts = 0;
let lastValue: T | undefined;
while (true) {
attempts += 1;
const elapsed = Date.now() - startTime;
if (elapsed >= maxDurationMs) {
return {
success: false,
value: lastValue as T,
attempts,
elapsedMs: elapsed,
reason: 'timeout',
};
}
try {
lastValue = await fetcher();
options.onProgress?.(attempts, elapsed);
if (condition(lastValue)) {
return {
success: true,
value: lastValue,
attempts,
elapsedMs: Date.now() - startTime,
reason: 'condition_met',
};
}
} catch (error) {
return {
success: false,
value: lastValue as T,
attempts,
elapsedMs: Date.now() - startTime,
reason: 'error',
error: error instanceof Error ? error.message : 'Unknown error',
};
}
await sleep(intervalMs);
}
}
