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

Run details:

User agent: Mozilla/5.0 (iPhone14,3; U; CPU iPhone OS 15_0 like Mac OS X) AppleWebKit/602.1.50 (KHTML, like Gecko) Version/10.0 Mobile/19A346 Safari/602.1

Browser: Mobile Safari 10

Operating system: iOS 15.0

Device Platform: Mobile

Date tested: 2 years ago

123456$(expr 879335345 + 912607992)

123K/s

123456

123K/s

View exact numbers

Test name	Executions per second
✓ 123456$(expr 879335345 + 912607992)	123,456 Ops/sec
✓ 123456	123,456 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]; }

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

save length of the array in the variable vs get it the loop

Cache length

Do not cache