Quick test to understand effect of mass amount of parallel promises in Node

promise-test.js

async function test(max) {

    const promises = [];

    if (max < 1000)
        throw new Error('max should be greater than 1000');

    for (let a = 0; a <= max; a++) {

        if (a === 0)
            console.time(`time-${max}-first`);

        if (a === 500)
            console.time(`time-${max}-500`);

        if (a === max)
            console.time(`time-${max}-last`);

        promises.push(promA(a, max));
    }

    await Promise.all(promises);

}

function promA(index, max) {
    return new Promise((resolve) => {

        console.info('started working on: ' + index);

        setTimeout(() => {

            if (index === 0)
                console.timeEnd(`time-${max}-first`);

            if (index === 500)
                console.timeEnd(`time-${max}-500`);

            if (index === max)
                console.timeEnd(`time-${max}-last`);

            console.info('actually resolved: ' + index);
            resolve(1);
        }, 0);
    });
}

async function run() {
    await test(1000);
    await test(10000);
    await test(100000);
    await test(1000000);
}

run()