Benchmark: Performance of JavaScript .loops

Script Preparation code:

const array = [];
for (let i = 0; i < 1000000; ++i) {
    result.push({
        a: i,
        b: i / 2,
        r: 0,
    });
}

Tests:

.forEach
array.forEach((x) => { x.r = x.a + x.b; });
for..of
for(const x of array) { x.r = x.a + x.b; }
for..of (destructuring)
const r = []; for(const {a, b} of array) { r.push(a + b); }
.map
array.map(x => x.a + x.b)
.map (destructuring)
array.map(({a,b}) => a + b)
.for (init array)
const r = new Array(array.length); for (let i = 0; i < array.length; ++i) { r[i] = array[i].a + array[i].b; }
.reduce
array.reduce((p, x) => p + x.a + x.b, 0);
.reduce (destructuring)
array.reduce((p, {a,b}) => p + a + b, 0);
for..of (reduce)
let r = 0; for (const x of array) { r += x.a + x.b; }
for..of (reduce) (destructuring)
let r = 0; for (const {a,b} of array) { r += a + b; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
.forEach
for..of
for..of (destructuring)
.map
.map (destructuring)
.for (init array)
.reduce
.reduce (destructuring)
for..of (reduce)
for..of (reduce) (destructuring)

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/133.0.0.0 Safari/537.36

Browser/OS: Chrome 133 on Windows

View result in a separate tab

for..of (reduce) (destructuring)

63.9M/s

for..of (reduce)

63.6M/s

for..of (destructuring)

63.2M/s

for..of

62.5M/s

.for (init array)

56.1M/s

.reduce (destructuring)

54.2M/s

.reduce

49.7M/s

.forEach

41.3M/s

.map

36.1M/s

.map (destructuring)

35.3M/s

View exact numbers

Test name	Executions per second
✓ for..of (reduce) (destructuring)	63,874,252 Ops/sec
for..of (reduce)	63,571,516 Ops/sec
for..of (destructuring)	63,171,200 Ops/sec
for..of	62,540,452 Ops/sec
.for (init array)	56,116,088 Ops/sec
.reduce (destructuring)	54,160,524 Ops/sec
.reduce	49,730,352 Ops/sec
.forEach	41,316,172 Ops/sec
.map	36,072,416 Ops/sec
.map (destructuring)	35,287,688 Ops/sec

Performance of JavaScript .loops (version: 1)

Comparing performance of: `.forEach vs for..of vs for..of (destructuring) vs .map vs .map (destructuring) vs .for (init array) vs .reduce vs .reduce (destructuring) vs for..of (reduce) vs for..of (reduce) (destructuring)`

Created: one year ago by: Registered User

Go to the latest result

.forEach

for..of

for..of (destructuring)

.map

.map (destructuring)

.for (init array)

.reduce

.reduce (destructuring)

for..of (reduce)

for..of (reduce) (destructuring)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Performance of JavaScript .loops (version: 1)

Comparing performance of: .forEach vs for..of vs for..of (destructuring) vs .map vs .map (destructuring) vs .for (init array) vs .reduce vs .reduce (destructuring) vs for..of (reduce) vs for..of (reduce) (destructuring)

Created: one year ago by: Registered User

Go to the latest result

.forEach

for..of

for..of (destructuring)

.map

.map (destructuring)

.for (init array)

.reduce

.reduce (destructuring)

for..of (reduce)

for..of (reduce) (destructuring)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `.forEach vs for..of vs for..of (destructuring) vs .map vs .map (destructuring) vs .for (init array) vs .reduce vs .reduce (destructuring) vs for..of (reduce) vs for..of (reduce) (destructuring)`