const services = ['a', 'b', 'c', 'd'];

async function foo(service) {

    // function to get one jobUrl data called by map later on
    const getJob = async ({ url: jobUrl }) => {
        const response = await fetch(jobUrl, { headers: headers });
        const { result, timestamp: timeStamp } = await response.json();
        if (result === 'SUCCESS') {
            return { jobUrl, timeStamp };
        }
    };

    // Find the list of jobs for a service
    let url = `http://example.com`;
    const response = await fetch(url, { method: 'POST', headers: headers });
    const { jobs } = await response.json();

    const unfiltered = await Promise.all(jobs.map(getJob));
    const successful = unfiltered.filter(v => v);

    let latestJob = successful.sort((obj1, obj2) => obj2.timeStamp - obj1.timeStamp)[0].jobUrl;
    let arr = latestJob.split('/');
    let recent = { service: service, job: arr[arr.length - 2] };
    console.log(recent);
    // return recent; 
}

When I run the following piece of code it takes only 4 seconds for finding the latest job.

for (const service of services) {
    foo(service);
}

Whereas, when I run the following piece of code it takes 15-16 seconds for finding the latest job. For this I uncomment the return recent; line of code in the last line of function foo and comment out the console.log(recent) line.

const latest = [];
for (const service of services) {
    latest.push(await foo(service));
}

My understanding is that for the second piece of code since we are waiting for all the async calls to finish it takes longer. If that is the case, is there a way to speed this up?