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

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?

CodePudding user response：

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);