Run results for: Caching length property vs getting it each time in the loop

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.84 Safari/537.36 HBPC/12.1.3.306

Browser: Chrome 99

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Cache length

15K/s

Do not cache

8K/s

View exact numbers

Test name	Executions per second
✓ Cache length	15,186 Ops/sec
Do not cache	7,618 Ops/sec

Script Preparation code:

var arr = [];
var count = 1000;
for(var i = 0; i<count; i++)
{
  arr.push(i);
}

Tests:

Cache length
var arrLen = arr.length; var sum = 0; for (var i = 0; i < arrLen; i++){ sum = arr[i]; }
Do not cache
var sum = 0; for (var i = 0; i < arr.length; i++){ sum = arr[i]; }