Run results for: Testing array lookup vs storing it in a variable first

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.0.0 Safari/537.36

Browser: Chrome 113

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
as i	4.9 Ops/sec
as vari	12.0 Ops/sec

Script Preparation code:

var arr = new Array(100_000)
for (let i=0; i< 100_000; ++i) {
	arr[i] = {
    	x1: Math.random(),
      	x2: Math.random(),
      	x3: Math.random(),
      	x4: Math.random(),
      	x5: Math.random()
    }
}

Tests:

as i
for (let i=0; i< arr.length; ++i) { arr[i].x1 += 10 arr[i].x2 += 10 arr[i].x3 += 10 arr[i].x4 += 10 arr[i].x5 += 10 }
as vari
for (let i=0; i< arr.length; ++i) { let iter = arr[i] iter.x1 += 10 iter.x2 += 10 iter.x3 += 10 iter.x4 += 10 iter.x5 += 10 }

Run results for: Testing array lookup vs storing it in a variable first

as i

as vari