Arrays jQuery.merge vs concat

JavaScript performance comparison

Revision 9 of this test case created

Info

Merge creates a smaller footprint because it loops through the original array and adds the new items. Concat is a built-in Javascript function and should be faster, but has a larger footprint.

Preparation code

<script src="http://code.jquery.com/jquery-git2.js"></script>
 
<script>
Benchmark.prototype.setup = function() {
      var array1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0];
   
      var array2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0];
};

Benchmark.prototype.teardown = function() {
    var array1 = undefined;
    var array2 = undefined;
};
</script>

Preparation code output

Test runner

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Testing in unknown unknown
Test Ops/sec
concat
array2 = array2.concat(array1);
console.log(array2.toString());
pending…
merge
console.log($.merge(array2, array1).toString());
pending…
push
for (elem in array1) {
  array2.push(elem);
}
console.log(array2.toString());
pending…

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