Run results for: JS loops and iterators

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Browser: Chrome 119

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Array.prototype.reduce

2.9M/s

For - of loop

746K/s

Array.prototype.forEach

275K/s

Optimised classic for loop

37K/s

Optimised while loop

37K/s

For - in loop

26K/s

While loop

19K/s

Classic for loop

18K/s

View exact numbers

Script Preparation code:

var array = new Array(1000).fill(Math.random(1000) * 1000);

Tests:

Classic for loop
let sum = 0; for (let i=0; i < array.length; i++) { sum += array[i]; }
Optimised classic for loop
let sum = 0; for (let i=0, len=array.length; i < len; i++) { sum += array[i]; }
While loop
let sum = 0; let i = 0; while (i < array.length) { sum += array[i]; i++; }
Optimised while loop
let sum = 0; let i = 0; let len = array.length; while (i < len) { sum += array[i]; i++; }
Array.prototype.forEach
let sum = 0; array.forEach(num => sum += num);
Array.prototype.reduce
const sum = array.reduce((acc, el) => acc + el, 0);
For - of loop
let sum = 0; for (let el of array) { sum += el; }
For - in loop
let sum = 0; for (let i in array) { sum += array[i]; }