Run results for: Array vs object performance by Dan 2

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 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
Array for each	15041.9 Ops/sec
Array for	8101.1 Ops/sec
Array map	7654.9 Ops/sec
Object for each	11874.4 Ops/sec
Object for in	2742.8 Ops/sec

Script Preparation code:

   var arr = [];
    for (var i = 0; i < 1000; i++) {
      arr[i] = i;
    }
  
    function someFn(i) {
      return i * 3 * 8;
    }
	
	var obj = {};
	for (var i = 0; i < 1000; i++) {
      obj[i] = i;
    }

Tests:

Array for each
arr.forEach(function (item){ someFn(item); })
Array for
for (var i = 0, len = arr.length; i < len; i++) { someFn(arr[i]); }
Array map
arr.map(item => someFn(item))
Object for each
Object.keys(obj).forEach(function(item) { someFn(item); });
Object for in
for (item in obj) { someFn(item); }

Run results for: Array vs object performance by Dan 2

Array for each

Array for

Array map

Object for each

Object for in