MeasureThat.net

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

Go to the benchmark
Run details:
Mozilla/5.0 (Windows Phone 10.0; Android 6.0.1; Microsoft; Lumia 950 XL Dual SIM) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.79 Mobile Safari/537.36 Edge/14.14915
Chrome Mobile 51
Windows Phone 10.0
Lumia 950
8 years ago
Test name Executions per second
Cache length 5576.0 Ops/sec
Do not cache 3919.2 Ops/sec
Script Preparation code:
AخA
 
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];
    }