Array Performance

JavaScript performance comparison

Revision 64 of this test case created

Info

Manual array lookups (array scans) vs. holey arrays vs. array lookups by index vs. object lookups.

Base test case: revision 29.

Changes:

Preparation code

<script>
  Benchmark.prototype.setup = function() {
    A1 = [];
    O1 = {};
    var amount=50000;
    for (var i=0; i < amount; i++) {
      A1.push({id: i, name: 'name1'});
      O1[''+i] = {id: i, name: 'name1'};
    }

    A2 = [];
    A2[20000] = {id: 20000, name: 'name1'};
    A2[30000] = {id: 30000, name: 'name1'};

    A3 = [{id: 20000, name: 'name1'}, {id: 30000, name: 'name1'}];
  };
</script>

Test runner

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Testing in unknown unknown
Test Ops/sec
Manual Array Lookup
var id = 30000, result, a = A1, l = a.length;
for (var i = 0; i < l; i++) {
  if (a[i].id == id) {
    result = a[i];
    break;
  }
}
pending…
Holey Array by Index
var id = 30000, result = A2[id];
pending…
Object by Key String (dynamic)
var id = 30000, result = O1[id.toString()];
pending…
Manual Array Lookup (small)
var id = 30000, result, a = A3, l = a.length;
for (var i = 0; i < l; i++) {
  if (a[i].id == id) {
    result = a[i];
    break;
  }
}
pending…
Object by Key Index
var id = 30000, result = O1[id];
pending…
Array by Index
var id = 30000, result = A1[id];
pending…
Object by Key String (static)
var id = "30000", result = O1[id];
pending…

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