Array direct assignment vs push

JavaScript performance comparison

Revision 68 of this test case created by Jare

Preparation code


      
      <script>
Benchmark.prototype.setup = function() {
  var values = [],
      count = 10000;
  
  for (var i = 0; i < count; i++) {
    values[i] = i;
  }

};
</script>

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
Direct assignment
var array = Array(count);
for (var i = 0; i < count; i++) {
  array[i] = values[i];
}
pending…
Push
var array = [];
for (var i = 0; i < count; i++) {
  array.push(values[i]);
}
pending…
Accessing length property
var array = [];
for (var i = 0; i < count; i++) {
  array[array.length] = values[i];
}
pending…
Cached length
var arrayLength = 0;
var array = [];
for (var i = 0; i < count; i++) {
    array[arrayLength++] = values[i];
}
pending…
Direct assignment using length
var array = [];
array.length = count;
for (var i = 0; i < count; i++) {
  array[i] = values[i];
}
pending…
push.apply
var array = [];
array.push.apply(Array(count))
for (var i = 0; i < count; i++) {
  array[i] = values[i];
}
pending…

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Revisions

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