for vs forEach

JavaScript performance comparison

Revision 238 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>

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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 
for (i = 0; i < values.length; sum += values[i], 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 ... in 
for (i in 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…

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