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 (Linux; Android 6.0.1; SM-G920V Build/MMB29K; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/52.0.2743.98 Mobile Safari/537.36
Chrome Mobile 52
Android 6.0.1
Samsung SM-G920V
8 years ago
Test name Executions per second
Cache length 4166.5 Ops/sec
Do not cache 2171.1 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];
    }