Run results for: Loop Optimization

Run details:

User agent: Mozilla/5.0 (Linux; Android 8.1.0; Nexus 6P Build/OPM3.171019.013) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.123 Mobile Safari/537.36

Browser: Chrome Mobile 64

Operating system: Android 8.1.0

Device Platform: Nexus 6P

Date tested: 2025 years ago

Test name	Executions per second
For loop, basic	64.8 Ops/sec
While loop, basic	67.4 Ops/sec
For loop, cached (inside for statement)	86.0 Ops/sec
For loop, cached (outside for statement)	89.8 Ops/sec
For loop, i-- (caching inside for loop)	91.8 Ops/sec
For loop, i-- (caching outside for loop)	89.9 Ops/sec
While loop, cached	112.0 Ops/sec
While loop, i--	105.7 Ops/sec
forEach	147.2 Ops/sec

Script Preparation code:

  var arr = [];
  for (var i = 0; i < 10000; i++) {
    arr.push(i);
  }

var sum = 0;

Tests:

For loop, basic
for (var i = 0; i < arr.length; i++) { sum += arr[i]; }
While loop, basic
var i = 0; while (i < arr.length) { sum += arr[i]; i++; }
For loop, cached (inside for statement)
for (var i = 0, len = arr.length; i < len; i++) { sum += arr[i]; }
For loop, cached (outside for statement)
var len = arr.length; for (var i = 0; i < len; i++) { sum += arr[i]; }
For loop, i-- (caching inside for loop)
for (var i = arr.length; i > 0; i--) { sum += arr[i]; }
For loop, i-- (caching outside for loop)
var i = arr.length; for (; i--;) { sum += arr[i]; }
While loop, cached
var len = arr.length; var i = 0; while(i < len){ sum += arr[i]; i++; }
While loop, i--
var i = arr.length; while(i--){ sum += arr[i]; }
forEach
arr.forEach(function(val){ sum += val; });

Run results for: Loop Optimization

Checking differences between various for/while loops.

For loop, basic

While loop, basic

For loop, cached (inside for statement)

For loop, cached (outside for statement)

For loop, i-- (caching inside for loop)

For loop, i-- (caching outside for loop)

While loop, cached

While loop, i--

forEach