Benchmark: for vs foreach vs for..of with sum

Script Preparation code:

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

Tests:

for
for (let i = 0; i < array.length; i++) { array[i].r = array[i].a + array[i].b; }
foreach
sum = x => x.r = x.a + x.b; array.forEach(sum);
for..of with reassign
for (let x of array) { x.r = x.a + x.b; }
for..of with no reassign
const result = []; for (let x of array) { result.push(x.a + x.b); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
for..of with reassign
for..of with no reassign

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:135.0) Gecko/20100101 Firefox/135.0

Browser/OS: Firefox 135 on Linux

View result in a separate tab

for

165/s

for..of with reassign

90/s

foreach

61/s

for..of with no reassign

42/s

View exact numbers

Test name	Executions per second
✓ for	165 Ops/sec
for..of with reassign	90 Ops/sec
foreach	61 Ops/sec
for..of with no reassign	42 Ops/sec

for vs foreach vs for..of with sum (version: 1)

Compare loop performance

Comparing performance of: `for vs foreach vs for..of with reassign vs for..of with no reassign`

Created: one year ago by: Guest

Go to the latest result

for

foreach

for..of with reassign

for..of with no reassign

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

for vs foreach vs for..of with sum (version: 1)

Compare loop performance

Comparing performance of: for vs foreach vs for..of with reassign vs for..of with no reassign

Created: one year ago by: Guest

Go to the latest result

for

foreach

for..of with reassign

for..of with no reassign

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `for vs foreach vs for..of with reassign vs for..of with no reassign`