for vs forEach (v160)

Revision 160 of this benchmark created on

Description

Is it faster to use the native forEach or just loop with for?

Inspired by Adrian Sutton's tests at: http://www.symphonious.net/2010/10/09/javascript-performance-for-vs-foreach/

This one adds random floating point numbers to see if the loop overhead is significant at all in the face of standard work.

Setup

var array = [];
    
    for( var i = 0; i < 1000; i++) {
        array.push(i);
    }
    
    function logIt(val){
        console.log(val);
    }
  };


Array.prototype.forEach2 = function (a, scope) {
            var l = this.length, i = 0;
            if(scope){
                for (; i < l; i++) {
                    a.call(scope, this[i], i);
                }
            }else{
                for (; i < l; i++) {
                    a(this[i], i);
                }
            }
        };
Array.prototype.forEach3 = function (a, scope) {
            var l = this.length, i = 0;
for (; i < l; i++) {
                    scope?a.call(scope, this[i], i):a(this[i], i);
                }

Test runner

Ready to run.

Testing in
TestOps/sec
for loop
for (i = 0, ii = array.length; i < ii; i++) {
  logIt(array[i]);
}
ready
forEach
array.forEach(logIt);
ready
for loop, reverse
for (i = array.length - 1; i >= 0; i--) {
  logIt(array[i]);
}
ready
for key in object
for (key in array) {
  logIt(array[key]);
}
ready
forEach with anonymous function
array.forEach(function(val) {
  console.log(val)
});
ready
foreach2
array.forEach2(logIt);
ready
foreach3
array.forEach3(logIt);
ready

Revisions

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