Run results for: Array foreach vs for..in

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:132.0) Gecko/20100101 Firefox/132.0

Browser: Firefox 132

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
for in	248363.8 Ops/sec
foreach	321834.8 Ops/sec

Script Preparation code:

var array = [];
for(let i = 0; i <= 100; i++) {
  array[i] = i;
}

Tests:

for in
let sum = 0; for (var sample in array) { sum += Number(sample); } console.log(sum);
foreach
let sum = 0; array.forEach((sample) => { sum += sample; }); console.log(sum);