Fastest array loops in Javascript

JavaScript performance comparison

Revision 396 of this test case created by

Preparation code

<script>
  // Populate the base array
  var arr = [];
  for (var i = 0; i < 1000; i++) {
    arr[i] = i;
  }

  function someFn(ix) {
    return ix * 5 + 1 / 3 * 8;
  }
</script>
    

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
For loop, basic
var l =  arr.length;
for (var i = 0; i < l; i++) {
  someFn(arr[i]);
}
pending…
While loop, basic
var i = 0;
var l = arr.length;
while (i++ < l) {
  someFn(arr[i]);
}
pending…
Order
while( i = arr.shift() ) {
  someFn(i);
}
pending…
order validation
while( (i = arr.shift()) !== undefined ) {
  someFn(i);
}
pending…
While ! Undefined
var a;
while((a = arr[i++]) !== undefined) {
  someFn(a);
}
pending…
Pop
while( i = arr.pop() ) {
  someFn(i);
}
pending…
Order w/ array copy
var copy = arr.slice(0);
while( i = copy.shift() ) {
  someFn(i);
}
pending…
While length--
var l = arr.length;
while(l--) {
  someFn(arr[l]);
}
pending…
123213
var n = arr.length;
var l = -n-1;
while(++l) {
  someFn(arr[l+n]);
}
pending…
Copy Pop
var copy = arr.slice();
while( i = copy.pop() ) {
  someFn(i);
}
pending…

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Revisions

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