Run results for: map vs for vs for (init array)

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36

Browser: Chrome 108

Operating system: Linux

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
map	21.1 Ops/sec
for	30.8 Ops/sec
for (init array)	38.0 Ops/sec

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;
}

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

Tests:

map

const array = generateTestArray();
array.map(x => x.a + x.b)

 
const array = generateTestArray();array.map(x => x.a + x.b)

for

const array = generateTestArray();
const r = [];
for (let i = 0, len = array.length; i < len; ++i) {
   r[i] = array[i].a + array[i].b;
}

 
const array = generateTestArray();const r = [];for (let i = 0, len = array.length; i < len; ++i) {   r[i] = array[i].a + array[i].b;}

for (init array)

const array = generateTestArray();
const r = new Array(array.length);
for (let i = 0, len = array.length; i < len; ++i) {
   r[i] = array[i].a + array[i].b;
}

 
const array = generateTestArray();const r = new Array(array.length);for (let i = 0, len = array.length; i < len; ++i) {   r[i] = array[i].a + array[i].b;}