How to replace Async/Await with Promise.AllSettled in a nested loop?

Question

I currently have the below code pulling data from an API and parsing it into my database. It takes up to 5 minutes since there can be up to 50 meets in a day, each with a dozen or so seperate events and each event has up to 20 runners. Think of it like an athletics meet. Sometimes this script is inserting 10,000 rows.

// Create Meetings
for (const meeting of meetingList) {
  const newMeeting = await createMeeting(meeting);

  // Create/Update Events
  for (const event of meeting.events) {
    await createEvent(event, newMeeting.id);

    // Create/Update Competitors
    for (const competitor of event.competitors) {
      await createCompetitor(competitor);
      await createRacingEventCompetitor(competitor, event.id);
    }
  }
}

Previously, I've used Promise.allSettled() as a nice way to make requests in parallel, saving significant time. How do I do the same when you have nested loops like in my example?

Answer 1

Simply create an array to hold the promises, called promises for example

Then push each request to that array instead of awaiting it

And await Promise.allSettled(promises)

Note: since newMeeting is required for the inner requests, you still need to await that ... though, there is a way you can avoid that too

But, this is a start

const promises = [];
for (const meeting of meetingList) {
  const newMeeting = await createMeeting(meeting);

  for (const event of meeting.events) {
    promises.push(createEvent(event, newMeeting.id));

    for (const competitor of event.competitors) {
      promises.push(createCompetitor(competitor));
      promises.push(createRacingEventCompetitor(competitor, event.id));
    }
  }
}
await Promise.allSettled(promises);

Not sure this is the BEST way to make everything parallel, but it is one way

const promises = [];
for (const meeting of meetingList) {
    promises.push(
        createMeeting(meeting)
        .then(newMeeting => {
            const innerPromises = [];
            for (const event of meeting.events) {
                innerPromises.push(createEvent(event, newMeeting.id));

                for (const competitor of event.competitors) {
                    innerPromises.push(createCompetitor(competitor));
                    innerPromises.push(createRacingEventCompetitor(competitor, event.id));
                }
            }
            return Promise.allSettled(innerPromises);
        })
    );
}
await Promise.allSettled(promises);