for vs forEach

JavaScript performance comparison

Revision 420 of this test case created by eviltwist

Preparation code

<script>
  var i, values = [],
      sum = 0;
  for (i = 0; i < 10000; i++) {
   values[i] = i;
  }
  
  function add(val) {
   sum += val;
  }

var obj = {
 add:add
};

function forIdx(arr,callback){
 var len = arr.length;
 for (i = 0; i < len; i++) {
  callback(i,arr[i]);
 }
}
function forIdx2(arr,callback,thisArg){
 var len = arr.length;
 for (i = 0; i < len; i++) {
  callback.call(thisArg, i,arr[i]);
 }
}
</script>
    

Test runner

Warning! For accurate results, please disable Firebug before running the tests. (Why?)

Java applet disabled.

Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
forEach
values.forEach(add);
pending…
for loop, simple
for (i = 0; i < values.length; i++) {
 add(values[i]);
}
pending…
for loop, cached length
var len = values.length;
for (i = 0; i < len; i++) {
 add(values[i]);
}
pending…
for loop, reverse
for (i = values.length - 1; i >= 0; i--) {
 add(values[i]);
}
pending…
forEach2
values.forEach((val) => { sum += val; });
pending…
forIdx
forIdx(values, function(idx, value){
add(value);
});
pending…
forIdx2
forIdx2(values, function(idx, value){
this.add(value);
},obj);
pending…

Compare results of other browsers

Revisions

You can edit these tests or add even more tests to this page by appending /edit to the URL.

0 Comments