Run results for: Looping through array

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.113 Safari/537.36

Browser: Chrome 53

Operating system: Windows

Device Platform: Other

Date tested: 8 years ago

Test name	Executions per second
Basic for loop	8156.5 Ops/sec
For loop but caching the length	630214.7 Ops/sec
While loop that imitates a for loop	8119.5 Ops/sec
While loop that imitates a for loop caching len	627630.3 Ops/sec
While loop in reverse simplifying the test	619832.8 Ops/sec
While looping by popping values	6114921.0 Ops/sec
for ... in loop	4116109.8 Ops/sec
for ... in loop with integer test	3842051.0 Ops/sec
For loop testing on existence rather than lengt	6594243.0 Ops/sec
For loop testing on existence plus array lookup	5880909.5 Ops/sec
For testing on existence rather than length array	6038332.0 Ops/sec
For reference	7409488.0 Ops/sec
Array.forEach() native implementation.	5811872.0 Ops/sec
For reference against forEach()	6668406.5 Ops/sec

Script Preparation code:

var arr = new Array(1000);

Tests:

Basic for loop
for (var i=0; i<arr.length; i++) {}
For loop but caching the length
for (var i=0, len=arr.length; i<len; i++) {}
While loop that imitates a for loop
var i = 0; while (i<arr.length) { i++; }
While loop that imitates a for loop caching len
var i=0, len=arr.length; while (i<len) { i++; }
While loop in reverse simplifying the test
var i = arr.length; while (i--) {}
While looping by popping values
var x; while (x = arr.pop()) {}
for ... in loop
for (var i in arr) {}
for ... in loop with integer test
var isInt = /(\^[0-9]$)|(\^[1-9][0-9]+$)/; for (var i in arr) { if(!isInt.test(i)){continue;} }
For loop testing on existence rather than lengt
for (var i=0; arr[i]; i++) {}
For loop testing on existence plus array lookup
for (var i=0; arr[i]; i++) { var x = arr[i]; }
For testing on existence rather than length array
for (var i=0, x; x = arr[i++];) {}
For reference
for (var i=0, len=arr.length; i<len; i++) { var x = arr[i]; }
Array.forEach() native implementation.
arr.forEach(function(x){});
For reference against forEach()
var f=function(x){}; for (var i=0, len=arr.length; i<len; i++) { f(arr[i]); }