Benchmark: flatMap vs reduce vs map

Script Preparation code:

var arr = Array(100).fill({
    portfolios: Array(100).fill(null)
});

Tests:

reduce
arr.reduce((acc, x) => {acc.push(...x.portfolios); return acc;}, [])
flatMap
arr.flatMap(x => x.portfolios)
map
arr.map(x => x.portfolios).flat()
foreach
const result = []; arr.forEach(x => result.push(...x.portfolios));
for of
const result = []; for(const x of arr) result.push(...x.portfolios);

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

flatMap

3K/s

map

3K/s

View exact numbers

✓ flatMap: 3,395 ops/sec
• map: 3,345 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
reduce
flatMap
map
foreach
for of

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36 Edg/134.0.0.0

Browser/OS: Chrome 134 on Windows

View result in a separate tab

for of

28K/s

foreach

26K/s

reduce

26K/s

map

11K/s

flatMap

10K/s

View exact numbers

Test name	Executions per second
✓ for of	27,676 Ops/sec
foreach	26,272 Ops/sec
reduce	26,163 Ops/sec
map	10,777 Ops/sec
flatMap	10,371 Ops/sec

flatMap vs reduce vs map (version: 6)

Comparing performance of: `reduce vs flatMap vs map vs foreach vs for of`

Created: one year ago by: Registered User

Go to the latest result

reduce

flatMap

map

foreach

for of

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

flatMap vs reduce vs map (version: 6)

Comparing performance of: reduce vs flatMap vs map vs foreach vs for of

Created: one year ago by: Registered User

Go to the latest result

reduce

flatMap

map

foreach

for of

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `reduce vs flatMap vs map vs foreach vs for of`