Run results for: Performance of JavaScript .forEach, .map and .reduce vs for and for..of with 1000p

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:142.0) Gecko/20100101 Firefox/142.0

Browser: Firefox 142

Operating system: Linux

Device Platform: Desktop

Date tested: 8 months ago

Test name	Executions per second
.forEach	54779.2 Ops/sec
for..of	52724.8 Ops/sec
for..of (destructuring)	45006.3 Ops/sec
.map	58509.6 Ops/sec
.map (destructuring)	56708.9 Ops/sec
.for (init array)	57086.6 Ops/sec
.reduce	47270.9 Ops/sec
.reduce (destructuring)	37423.3 Ops/sec
for..of (reduce)	40490.9 Ops/sec
for..of (reduce) (destructuring)	57006.4 Ops/sec

Script Preparation code:

function generateTestArray() {
  const result = [];
  for (let i = 0; i < 1000; ++i) {
    result.push({
      a: i,
      b: i / 2,
      r: 0,
    });
  }
  return result;
}

Tests:

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

Run results for: Performance of JavaScript .forEach, .map and .reduce vs for and for..of with 1000p

.forEach

for..of

for..of (destructuring)

.map

.map (destructuring)

.for (init array)

.reduce

.reduce (destructuring)

for..of (reduce)

for..of (reduce) (destructuring)