Array Performance

JavaScript performance comparison

Revision 56 of this test case created


Manual array lookups vs. holey arrays.

Preparation code

  Benchmark.prototype.setup = function() {
    var a1 = [];
    var o = {};
    for (var i=0;i<33000;++i){
        a1.push({id:i, name:"name1"});
        o[i] = {id:i, name:"name1"};

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


Test runner

Warning! For accurate results, please disable Firebug before running the tests. (Why?)

Java applet disabled.

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];
Holey Array by Index
var id = 29938;
var result = a2[id];
Object by Key
var id = '29938';
var result = o[id];

Compare results of other browsers


You can edit these tests or add even more tests to this page by appending /edit to the URL. Here’s a list of current revisions for this page:


Comment form temporarily disabled.

Add a comment