Array Performance

JavaScript performance comparison

Revision 25 of this test case created by David Bonnet

Info

Manual array lookups vs. holey arrays.

Preparation code

<script>
  Benchmark.prototype.setup = function() {
    a1 = [];
    var amount=35000;
    for (var i=0; i < amount; i++) {
      a1.push({id: i, name: 'name1'});
    }

    a2 = [];
    a2[29938] = {id: 29938, name: 'name1'};
    a2[32994] = {id: 32994, name: 'name1'};

    a3 = [{id: 29938, name: 'name1'}, {id: 32994, name: 'name1'}];

    var o1 = {};
    o1[29938] = {id: 29938, name: 'name1'};
    o1[32994] = {id: 32994, name: 'name1'};
  };
</script>

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Testing in unknown unknown
Test Ops/sec
Manual Array Lookup
var id = 29938, result, l = a1.length;
for (var i = 0; i < l; i++) {
  if (a1[i].id = id) {
    result = a1[i];
    break;
  }
}
pending…
Holey Array by Index
var id = 29938, result = a2[id];
pending…
Object by Key
var id = 29938, result = o1[id];
pending…
Manual Array Lookup (small)
var id = 29938, result, l = a3.length;
for (var i = 0; i < l; i++) {
  if (a3[i].id = id) {
    result = a3[i];
    break;
  }
}
pending…

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