Underscore.each vs jQuery.each vs. for loop

JavaScript performance comparison

Revision 31 of this test case created by Bruno Windels

Preparation code

<script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js">
</script>
<script src="//documentcloud.github.com/underscore/underscore-min.js">
</script>
<script>
  var pi = Math.PI
  var a = new Array(100000),
      e;
  
  var ArrayIterator = function(array) {
        this.array = array;
        this.index = -1;
  };
  
  ArrayIterator.prototype.next = function() {
        return this.index<(this.array.length-1);
  };
  
  ArrayIterator.prototype.current = function() {
        this.index += 1;
        return this.array[this.index];
  };
</script>

Preparation code output

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Testing in unknown unknown
Test Ops/sec
jQuery.each
 
$.each(a, function() {
  e = pi;
});
 pending…
good old for loop
 
for (var i = 0, len = a.length; i < len; i++) {
  e = pi;
};
 pending…
underscore.each
 
_.each(a, function(item) {
  e = pi;
});
 pending…
good old for loop (decrementing)
 
var i = a.length;
for (; i > 0; i--) {
  e = pi;
};
 pending…
another loop
 
var len = a.length,i=0;
for(;i<len;i+=1){e=pi};
 pending…
Iterator pattern
 
var it = new ArrayIterator(a);
while(it.next()) {
  e = it.current();
}
 pending…

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Revisions

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1 comment

Bradford commented : ∞

So, why are underscore.js and jquery so slow? Is it because of .call and .apply?

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