Recursive yield called from setTimeout

Question

I'm consuming an API with rate-limit, every time a hit my rate limit it returns header retry-after specifying the amount of seconds to wait for rate limit reset.

I need to:

• Send 100 calls with Promise.allSettled([...]);
• Some requests will succeed then process it;
• Retry rejected requests after specified seconds.

My solution so far:

async *indicators(items: string[]): AsyncIterableIterator<any[]> {
  const res = await Promise.allSettled(items.map((item) => this.makeRequest(item)))

  const fulfilledRequests = res.filter((r) => r.status === 'fulfilled') as PromiseFulfilledResult<any>[]

  for (const { value } of fulfilledRequests) {
    console.log('Yielding')
    yield value
    console.log('Yielded')
  }

  const rejectedRequest = res.find((r) => r.status === 'rejected') as any
  const failedItems = res.filter((p) => p.status === 'rejected').map(({ reason }: any) => reason.item)

  if (failedItems.length === 0 || !failedItems?.reason?.retryAfter)
    return Logger.log(`No more items to check`)

  setTimeout(this.indicators(failedItems).next.bind(this), rejectedRequest.reason.retryAfter)
}

async makeRequest(item: string): Promise<Indicator[]> {
  try {
    const { data: { data } } = await firstValueFrom(this.httpService.post('https://api.io', { item }))
    return data
  } catch (error) {
    throw { retryAfter: error.response.headers['retry-after'] * 1000, symbol }
  }
}

main() {

  for await (const item of this.indicators(['', ''])) {
    console.log(item)
  }

}

• First iterations runs fine, from 100 items it fetches 30 and yields as expected;
• Then setTimeout is working as expected;
• Indicators functions runs for the second time;
• The request works;
• The first Yielding log is shown and then it stops.

I'm using NestJS with Typescript on Node v16.

Answer 1

I made it working by using a do while loop awaiting for retry after time.

async *listMeetings(meetingIds: string[]): AsyncIterableIterator<MeetingResponse> {
  let hasMore = false
  do {
    const res = await Promise.allSettled(meetingIds.map((id) => this.makeRequest(id)))
    const fulfilledRequests = res.filter((r) => r.status === 'fulfilled')
    for (const { value } of fulfilledRequests) {
      yield value
    }
    const rejectedRequest = res.find((r) => r.status === 'rejected')
    const failedMeetings = res.filter((p) => p.status === 'rejected').map(({ reason }: any) => reason.meetingId)
    if (failedMeetings.length === 0 || !rejectedRequest?.reason?.retryAfter) {
      hasMore = false
    } else {
      await new Promise<void>((resolve) => setTimeout(() => resolve(), rejectedRequest.reason.retryAfter))
      yield* this.listMeetings(failedMeetings)
    }
  } while (hasMore)
}

main() {
  for await (const meeting of this.client.listMeetings([])) {
    console.log(meeting)
  }
}