Benchmark: .filter().map() vs flatMap() vs reduce()

Tests:

.filter().map()
const filteredData = data .filter(i => i.index % 2 === 0) .map(i => i.index);
.flatMap()
const filteredData = data.flatMap(i => i.index % 2 === 0 ? [i.index] : []);
.reduce()
const filteredData = data.reduce((memo, i) => { if (i.index % 2 === 0) { memo.push(i.index); } return memo; }, []);
for ... of
const filteredData = []; for (let i of data) { if (i.index % 2 === 0) { filteredData.push(i.index); } }
regular for
const filteredData = []; for (let i = 0; i < data.length; i++) { if (data[i].index % 2 === 0) { filteredData.push(data[i].index); } }
regular for, prefilled then trimmed
let filteredData = Array.from({length: data.length}); let filteredIndex = 0; for (let i = 0; i < data.length; i++) { if (data[i].index % 2 === 0) { filteredData[filteredIndex++] = data[i].index; } } filteredData = filteredData.splice(filteredIndex, data.length - filteredIndex);

Historical Performance Data aggregated from 6 community runs

Desktop Results:

Chrome 6 runs

for ... of

8K/s

.reduce()

3K/s

regular for

2K/s

.filter().map()

1K/s

.flatMap()

1K/s

regular for, prefilled then trimmed

579/s

Fastest: for ... of (13.7x faster)

View exact numbers

✓ for ... of: 7,950 ops/sec
• .reduce(): 2,653 ops/sec
• regular for: 2,495 ops/sec
• .filter().map(): 1,323 ops/sec
• .flatMap(): 1,171 ops/sec
• regular for, prefilled then trimmed: 579 ops/sec

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

Test case name	Result
.filter().map()
.flatMap()
.reduce()
for ... of
regular for
regular for, prefilled then trimmed

Latest run results:

Run details: (Test run date: 4 months ago)

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/146.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 146 on Android

View result in a separate tab

for ... of

5K/s

regular for

1K/s

.reduce()

1K/s

.filter().map()

668/s

.flatMap()

586/s

regular for, prefilled then trimmed

255/s

View exact numbers

Test name	Executions per second
✓ for ... of	4,897 Ops/sec
regular for	1,268 Ops/sec
.reduce()	1,165 Ops/sec
.filter().map()	668 Ops/sec
.flatMap()	586 Ops/sec
regular for, prefilled then trimmed	255 Ops/sec

.filter().map() vs flatMap() vs reduce() (version: 2)

Compare performance of `.filter().map()`, `flatMap()`, and `reduce()` in JavaScript

Comparing performance of: `.filter().map() vs .flatMap() vs .reduce() vs for ... of vs regular for vs regular for, prefilled then trimmed`

Created: one year ago by: Registered User

Go to the latest result

.filter().map()

.flatMap()

.reduce()

for ... of

regular for

regular for, prefilled then trimmed

Historical Performance Data aggregated from 6 community runs

Desktop Results:

Chrome 6 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

.filter().map() vs flatMap() vs reduce() (version: 2)

Compare performance of `.filter().map()`, `flatMap()`, and `reduce()` in JavaScript

Comparing performance of: .filter().map() vs .flatMap() vs .reduce() vs for ... of vs regular for vs regular for, prefilled then trimmed

Created: one year ago by: Registered User

Go to the latest result

.filter().map()

.flatMap()

.reduce()

for ... of

regular for

regular for, prefilled then trimmed

Historical Performance Data aggregated from 6 community runs

Desktop Results:

Chrome 6 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `.filter().map() vs .flatMap() vs .reduce() vs for ... of vs regular for vs regular for, prefilled then trimmed`