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

Test name

Executions per second

✓ .reduce

47 Ops/sec

.forEach

45 Ops/sec

for..of

44 Ops/sec

.reduce (destructuring)

43 Ops/sec

for..of (reduce)

42 Ops/sec

for..of (reduce) (destructuring)

42 Ops/sec

.for (init array)

38 Ops/sec

.map

37 Ops/sec

.map (destructuring)

35 Ops/sec

for..of (destructuring)

34 Ops/sec

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; }