Array direct assignment vs push

JavaScript performance comparison

Revision 90 of this test case created by hve

Preparation code


      
      <script>
Benchmark.prototype.setup = function() {
  var array = [];
  var array2 = [];
  array2.len = 0;
  var other_array = 0 ;
  var count = 100;
  var array_push = function (arr, item) {
     arr[arr.length] = item;
  };

};
</script>

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
array2.len
for(var i = 0; i < count; i++)
{
  array2[array2.len++] = Math.random();
}
array[count] = (count = count + 200);
count = count % 200;
pending…
Direct assignment via function
for (var i = 0; i < count; ++i) {
   array_push(array2, Math.random());
}
array[count] = (count = count + 200);
count = count % 200;
pending…
Using concat
for (var i = 0; i < count; ++i) {
   array.concat(Math.random());
}
array[count] = (count = count + 200);
count = count % 200;
pending…
Direct assignment
for(var i = 0; i < count; i++)
{
  array[i] = Math.random();
}
array[count] = (count = count + 200);
count = count % 200;
pending…
Push
for(var i = 0; i < count; i++)
{
  array.push(Math.random());
}
array[count] = (count = count + 200);
count = count % 200;
pending…
Direct assignment (calculated)
for(var i = 0; i < count; i++)
{
  array[array.length] = Math.random();
}
array[count] = (count = count + 200);
count = count % 200;
pending…
other
for(var i = 0; i < count; i++)
{
  array[other_array++] = Math.random();
}
array[count] = (count = count + 200);
count = count % 200;
pending…

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