Run results for: Array loop

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.100 Safari/537.36

Browser: Chrome 75

Operating system: Mac OS X 10.14.5

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
Standard For loop i++	8.4 Ops/sec
Standard For loop i--	8.0 Ops/sec
While, i--	8.0 Ops/sec
While, with 8 iterations, with function call	66.3 Ops/sec
While, with 8 iterations, without function call	129.8 Ops/sec
While, with 50 iterations, with function call	391.2 Ops/sec

Script Preparation code:

var loopItems = [];
var i = 0;

for (i = 0; i < 1000000; i++) {
	loopItems.push(Math.random());
}

var process = function (i) {
	i++;
}

Tests:

Standard For loop i++
i = loopItems.length; for (var j = 0; j < i; j++) { process(loopItems[j]); }
Standard For loop i--
i = loopItems.length; for (var j = i; j > 0; j--) { process(loopItems[j]); }
While, i--
i = loopItems.length; while (i) { process(loopItems[i--]); }
While, with 8 iterations, with function call
i = Math.floor(loopItems.length / 8); while (i) { process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); }
While, with 8 iterations, without function call
i = Math.floor(loopItems.length / 8); while (i) { loopItems[i--]++; loopItems[i--]++; loopItems[i--]++; loopItems[i--]++; loopItems[i--]++; loopItems[i--]++; loopItems[i--]++; loopItems[i--]++; }
While, with 50 iterations, with function call
i = Math.floor(loopItems.length / 50); while (i) { process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); process(loopItems[i--]); }

Run results for: Array loop

Standard For loop i++

Standard For loop i--

While, i--

While, with 8 iterations, with function call

While, with 8 iterations, without function call

While, with 50 iterations, with function call