Fastest array loops in Javascript

JavaScript performance comparison

Revision 266 of this test case created by

Preparation code 

<script>
  // Populate the base array
  var arr = [];
  for (var i = 0; i < 1000; i++) {
    arr[i] = 'value' + 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 
for (var i = 0; i < arr.length; i++) {
  someFn(i);
}
 pending…
While loop, basic 
var i = 0;
while (i < arr.length) {
  someFn(i);
  i++;
}
 pending…
For loop, cached 
for (var i = 0, len = arr.length; i < len; i++) {
  someFn(i);
}
 pending…
For loop, i-- 
for (var i = arr.length; i > 0; i--) {
  someFn(i);
}
 pending…
For loop, i -= 1 II 
var i;
for (i = arr.length; i > 0; i -= 1) {
  someFn(i);
}
 pending…
For loop 
var i;
for (i = arr.length; i > 0; i--) {
  someFn(i);
}
 pending…
For loop1 
for (var i = arr.length; i--;) {
  someFn(i);
}
 pending…
Do-while loop, i-- 
var i = arr.length - 1;
do {
  someFn(i);
}
while (i--);
 pending…
Do-while loop, --i 
var i = arr.length;
if (i > 0) {
  do {
    someFn(i);
  }
  while (--i);
}
 pending…
For..in loop 
for (var i in arr) {
  someFn(i);
}
 pending…
while loop i-- 
var i = arr.length;
while (i--) {
  someFn(i);
}
 pending…
For loop, i -= 1 
for (var i = arr.length; i > 0; i -= 1) {
  someFn(i);
}
 pending…

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