Run results for: fight to the death - for loop vs chained array methods (100,000)

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser: Chrome 130

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
for loop (added a sort on the end to even things up)	32.3 Ops/sec
chained arr methods	186.9 Ops/sec

Script Preparation code:

const randomStDate = () => {
    const randD = new Date(new Date("2021-12-05").getTime() + Math.random() * (new Date("2026-12-05").getTime() - new Date("2023-12-05").getTime()))
    let month = '' + (randD.getMonth() + 1);
    let day = '' + randD.getDate();
    let year = randD.getFullYear();
    if (month.length < 2) month = '0' + month;
    if (day.length < 2) day = '0' + day;
    return [year, month, day].join('-');

};

const rndId = Math.floor(Math.random() * (100000000 - 1 + 1) + 1)

const createArr = () => {
    let workArr = []
    for (let i = 0; i < 100000; i++) {
        const pl = {
            tisId: rndId,
            startDate: randomStDate(),
            endDate: "2026-12-05",
            site: "Liverpool",
        }
        workArr.push(pl)

    }
    return workArr
}

var workArr = createArr()
var today = new Date().toISOString().slice(0, 10)

Tests:

for loop (added a sort on the end to even things up)
let pastArr = []; let futureArr = []; for (let i = 0; i < workArr.length; i++) { const pl = workArr[i]; switch(true){ case pl.startDate <= today : pastArr.push(pl); break; case futureArr.length < 1 && pl.startDate > today : futureArr = [pl]; break; case futureArr.length > 0 && pl.startDate < futureArr[0].startDate : futureArr = [pl]; break; case futureArr.length > 0 && pl.startDate === futureArr[0].startDate : futureArr.push(pl); break; } } return [...pastArr, ...futureArr].sort((a, b) => (a.startDate > b.startDate ? 1 : -1));
chained arr methods
const firstFutureWorks = workArr .filter(w => w.startDate > today) .sort((a, b) => (a.startDate > b.startDate ? 1 : -1)); const nextFutureDate = firstFutureWorks[0] ? firstFutureWorks[0].startDate : today; return workArr.filter(w => w.startDate <= nextFutureDate);

Run results for: fight to the death - for loop vs chained array methods (100,000)

array length 100,000

for loop (added a sort on the end to even things up)

chained arr methods