Benchmark: Object.groupBy vs manual groupBy object vs manual groupBy Map

Script Preparation code:

function groupByObj(array, mapper) {
    return array.reduce(
        (acc, item) => {
            const key = mapper(item);
            const items = acc[key] ?? (acc[key] = []);
            items.push(item);
            return acc;
        }, {},
    );
}

function groupByMap1(array, mapper) {
    return array.reduce(
        (acc, item) => {
            const key = mapper(item);
            let items = acc.get(key);
            if (!items) {
              items = []
              acc.set(key, items)
            }
            items.push(item);
            return acc;
        }, new Map(),
    );
}

function groupByMap2(array, mapper) {
    return array.reduce(
        (acc, item) => {
            const key = mapper(item);
            if (!acc.has(key)) {
              acc.set(key, [item])
            } else { acc.get(key).push(item) }
            return acc;
        }, new Map(),
    );
}

function makeid(length) {
    var result = '';
    var characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    var charactersLength = characters.length;
    for (var i = 0; i < length; i++) {
        result += characters.charAt(Math.floor(Math.random() * charactersLength));
    }
    return result;
}

function randomIntFromInterval(min, max) { // min and max included 
    return Math.floor(Math.random() * (max - min + 1) + min);
}

var data = []

for (let i = 0; i < 1000; i++) {
    data.push({
        name: makeid(randomIntFromInterval(5, 16)),
        age: randomIntFromInterval(1, 100),
        occupation: Math.random() > 0.8 ? makeid(randomIntFromInterval(5, 16)) : null
    })
}

Tests:

Object.groupBy
return Object.groupBy(data, item => item.occupation)
Manual groupBy obj
return groupByObj(data, item => item.occupation)
Manual groupBy map 1
return groupByMap1(data, item => item.occupation)
Manual groupBy map 2
return groupByMap2(data, item => item.occupation)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.groupBy
Manual groupBy obj
Manual groupBy map 1
Manual groupBy map 2

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36

Browser/OS: Chrome 141 on Mac OS X 10.15.7

View result in a separate tab

Manual groupBy map 1

82K/s

Manual groupBy obj

76K/s

Manual groupBy map 2

71K/s

Object.groupBy

48K/s

View exact numbers

Test name	Executions per second
✓ Manual groupBy map 1	82,303 Ops/sec
Manual groupBy obj	75,669 Ops/sec
Manual groupBy map 2	71,309 Ops/sec
Object.groupBy	48,293 Ops/sec

Object.groupBy vs manual groupBy object vs manual groupBy Map (version: 1)

Comparing performance of: `Object.groupBy vs Manual groupBy obj vs Manual groupBy map 1 vs Manual groupBy map 2`

Created: 9 months ago by: Registered User

Go to the latest result

Object.groupBy

Manual groupBy obj

Manual groupBy map 1

Manual groupBy map 2

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Object.groupBy vs manual groupBy object vs manual groupBy Map (version: 1)

Comparing performance of: Object.groupBy vs Manual groupBy obj vs Manual groupBy map 1 vs Manual groupBy map 2

Created: 9 months ago by: Registered User

Go to the latest result

Object.groupBy

Manual groupBy obj

Manual groupBy map 1

Manual groupBy map 2

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `Object.groupBy vs Manual groupBy obj vs Manual groupBy map 1 vs Manual groupBy map 2`