for vs forEach when n is <= 10 (v342)

Revision 342 of this benchmark created by mvince on

Description

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

Inspired by Adrian Sutton's tests at: http://www.symphonious.net/2010/10/09/javascript-performance-for-vs-foreach/

This one adds random floating point numbers to see if the loop overhead is significant at all in the face of standard work.

Preparation HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js">
</script>

Setup

var i,
      value,
      length,
      values = [],
      sum = 0,
      context = values;
    
    
    for (i = 0; i < 10; i++) {
      values[i] = Math.random();
    }
    
    function add(val) {
      sum += val;
    }

Teardown


    i = 0;
    value = 0;
    length = 0;
    values = [];
    sum = 0;

Test runner

Ready to run.

Testing in
TestOps/sec
forEach
values.forEach(add);
ready
for loop, simple
for (i = 0; i < values.length; i++) {
  sum += values[i];
}
ready
for loop, cached length
length = values.length;
for (i = 0; i < length; i++) {
  sum += values[i];
}
ready
for loop, reverse
for (i = values.length - 1; i >= 0; i--) {
  sum += values[i];
}
ready
for loop, cached length, callback
length = values.length;
for (i = 0; i < length; i++) {
  add(values[i], i, values);
}
ready
for loop, cached length, callback.call
length = values.length;
for (i = 0; i < length; i++) {
  add.call(context, values[i], i, values);
}
ready
$.each
$.each(values, function(key, value) {
  sum += value;
});
ready
for ... in
for (i in values) {
  sum += values[i];
}
ready
for loop, reverse, decrement condition
for (i = values.length; i--;) {
  sum += values[i];
}
ready
for loop, reverse, pre-decrement
for (i = values.length - 1; i >= 0; --i) {
  sum += values[i];
}
ready
for loop, assignment condition
for (i = 0;
  (value = values[i]) !== undefined; i++) {
  sum += value;
}
ready
for loop, assignment condition, reversed
for (i = values.length - 1;
  (value = values[i]) !== undefined; i--) {
  sum += value;
}
ready
for loop, assignment condition, callback
for (i = 0;
  (value = values[i]) !== undefined; i++) {
  add(value, i, values);
}
ready
for loop, assignment condition, callback.call
for (i = 0;
  (value = values[i]) !== undefined; i++) {
  add.call(context, value, i, values);
}
ready

Revisions

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