Fastest array loops in Javascript

JavaScript performance comparison

Revision 533 of this test case created by jon

Preparation code

<script>
  function someFn(ix) {
    try { 
        ix += 1; 
        if (ix < 0) {
           throw new Error('e');
        }
    } catch (e){
        alert(e);
    }
    return ix * 5 + 1 / 3 * 8;
  }
  
var testArr = [];
for (i = 0; i < 1000; i++) {
	testArr[i] = i+1;
}

</script>
      
<script>
Benchmark.prototype.setup = function() {
  // Populate the base array
  var arr = testArr.slice();

};
</script>

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
For loop, basic
var i;
for (i = 0; i < arr.length; i++) {
  someFn(arr[i]);
}
pending…
While loop, basic
var i = 0;
while (i != arr.length) {
  someFn(arr[i++]);
}
pending…
For loop, cached
var i, len;
for (i = 0, len = arr.length; i < len; i++) {
  someFn(arr[i]);
}
pending…
For loop, i--
var i;
for (i = arr.length; i > 0; i--) {
  someFn(arr[i]);
}
pending…
Do-while loop, i--
var i = arr.length - 1;
if (i >= 0) {
	do {
	  someFn(arr[i]);
	} while (i--);
}
pending…
Do-while loop, --i
var i = arr.length;
if (i > 0) {
  do {
    someFn(arr[i - 1]);
  } while (--i);
}
pending…
For..in loop
var i;
for (i in arr) {
  someFn(arr[i]);
}
pending…
forEach
arr.forEach(function (v){
  someFn(v);
});
pending…
While ! Undefined
var i = 0, v;
while((v = arr[i++]) !== undefined) {
  someFn(v);
}
pending…
While length--
var i = arr.length;
while(i--) {
  someFn(arr[i]);
}
pending…
For of
var v;
for (v of arr) {
	someFn(v);
}
pending…
while arithmetic in condition
var i = 0;
while (i != arr.length + 1 - 1) {
  someFn(arr[i++]);
}
pending…

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Revisions

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