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

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.95 Safari/537.36

Browser: Chrome 55

Operating system: Mac OS X 10.11.3

Device Platform: Other

Date tested: 7 years ago

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]; }
Reverse
var arrLen = arr.length; var sum = 0; for (var i = arrLen; i !== 0; i--){ sum = arr[i]; }
Reverse Opt
var arrLen = arr.length; var sum = 0; for (; arrLen !== 0; arrLen--){ sum = arr[arrLen]; }