for vs forEach

JavaScript performance comparison

Revision 475 of this test case created by

Preparation code

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js">
</script>
      
<script>
Benchmark.prototype.setup = function() {
  var i,
    value,
    length,
    values = [],
    sum = 0,
    context = values;
  
  
  for (i = 0; i < 10000; i++) {
    values[i] = Math.random();
  }
  
  function add(val) {
    sum += val;
  }

};

Benchmark.prototype.teardown = function() {
  i = 0;
  value = 0;
  length = 0;
  values = [];
  sum = 0;

};
</script>

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
forEach
values.forEach(add);
pending…
for loop, simple
for (i = 0; i < values.length; i++) {
  sum += values[i];
}
pending…
for loop, cached length
length = values.length;
for (i = 0; i < length; i++) {
  sum += values[i];
}
pending…
for loop, reverse
for (i = values.length - 1; i >= 0; i--) {
  sum += values[i];
}
pending…
for loop, cached length, callback
length = values.length;
for (i = 0; i < length; i++) {
  add(values[i], i, values);
}
pending…
for loop, cached length, callback.call
length = values.length;
for (i = 0; i < length; i++) {
  add.call(context, values[i], i, values);
}
pending…
$.each
$.each(values, function(key, value) {
  sum += value;
});
pending…
for ... of
for (i of values) {
  sum += values[i];
}
pending…
for loop, reverse, decrement condition
for (i = values.length; i--;) {
  sum += values[i];
}
pending…
for loop, reverse, pre-decrement
for (i = values.length - 1; i >= 0; --i) {
  sum += values[i];
}
pending…
for loop, assignment condition
for (i = 0;
  (value = values[i]) !== undefined; i++) {
  sum += value;
}
pending…
for loop, assignment condition, reversed
for (i = values.length - 1;
  (value = values[i]) !== undefined; i--) {
  sum += value;
}
pending…
for loop, assignment condition, callback
for (i = 0;
  (value = values[i]) !== undefined; i++) {
  add(value, i, values);
}
pending…
for loop, assignment condition, callback.call
for (i = 0;
  (value = values[i]) !== undefined; i++) {
  add.call(context, value, i, values);
}
pending…
for loop, reverse, decrement condition, cached length, callback.call
var length = values.length;
for (var i = length; i--;) {
  add.call(context, values[i], i);
}
pending…
for loop, reverse, decrement condition, cached length
var length = values.length;
for (i = length - 1; i >= 0; --i) {
  sum += values[i];
}
pending…
Simple Define Vars Outside Loop ++
var i=0
, len = values.length
;

for (; i < len; i++) {
  sum += values[i];
}
pending…
Simple Define Vars Outside Loop --
var len = values.length
, i = len - 1
;

for (; i >= 0; i--) {
  sum += values[i];
}
pending…
Simple Define Vars Outside Loop += 1
var i=0
, len = values.length
;

for (; i < len; i+= 1) {
  sum += values[i];
}
pending…

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Revisions

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