Run results for: for..of vs for simple vs for..in - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:82.0) Gecko/20100101 Firefox/82.0

Browser: Firefox 82

Operating system: Ubuntu

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
for..of	4015312.2 Ops/sec
for..in	347181.1 Ops/sec
for	3924198.5 Ops/sec
foreach	4351589.5 Ops/sec

Script Preparation code:

var arr = [12342, 342, 3423, 432, 432, 423, 43, 3, 1, 321, 323, 1, 31, 31, 31, 231, 31, 31];

Tests:

for..of
const narr = []; for(const item of arr){ narr.push(item) }
for..in
const narr = []; for(const item in arr){ narr.push(arr[item]) }
for
const narr = []; for(let i=0; i<arr.length; i++){ narr.push(arr[i]) }
foreach
const narr = []; arr.forEach( e => narr.push(e));