for vs forEach vs while

JavaScript performance comparison

Revision 60 of this test case created

Info

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

Preparation code

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

  function add(val) {
    sum += val;
  }
</script>

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Testing in unknown unknown
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…
for in loop
for (var i in values) {
  add(values[i]);
}
pending…
for loop, equality comparison
for (i = 0; i !== values.length; i++) {
  add(values[i]);
}
pending…
for loop, equality comparison, cached length
var len = values.length;
for (i = 0; i !== len; i++) {
  add(values[i]);
}
pending…
while loop, reversed
var len = values.length;
while (len) {
  add(values[--len]);
}
pending…
while loop, reversed, ordered
// if order matters
var len, i;
len = i = values.length;
while (i) {
  add(values[len - (i--)]);
}
pending…

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