Array Performance

JavaScript performance comparison

Revision 51 of this test case created

Info

Manual array lookups vs. holey arrays.

Preparation code

<script>
  Benchmark.prototype.setup = function() {

    var a1 = [], a2 = [], o = {};
    var tempId = 0;

    for (var i = 1; i <= 500; i++) {
       tempId = 29700 + i;
       a1.push({id: tempId, name: 'name' + tempId});
       a2[tempId] = {id: tempId, name: 'name' + tempId};
       o[tempId.toString()] = {id: tempId, name: 'name' + tempId};
    }
  };
</script>

Test runner

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Testing in unknown unknown
Test Ops/sec
Manual Array Lookup
var id = 29938;
for (var i = 0; i < a1.length; i++) {
  if (a1[i].id = id) result = a1[i];
}
 
pending…
Holey Array by Index
var id = 29938;
var result = a2[id];
pending…
Object by Key
var id = '29938';
var result = o[id];
 
pending…
Manual Array Lookup
var id = 29938;
for (var i = a1.length-1; i >= 0; i--) {
  if (a1[i].id = id) result = a1[i];
}
 
pending…

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