Preparation code

<script>
  function protoArray() {
    var i = 0;
    var a = [];
    var p = {foo: 0};
    p.__proto__ = Array.prototype;
    a.__proto__ = p;
    for (i = 0; i < 10000; i++) {
      a[i] = i;
    }
    var sum = 0;
    var l = a.length;
    for (i = 0; i < l; i++) {
      sum += a[i];
    }
    return sum;
  }

  function plainArray() {
    var i = 0;
    var a = [];
    for (i = 0; i < 10000; i++) {
      a[i] = i;
    }
    var sum = 0;
    var l = a.length;
    for (i = 0; i < l; i++) {
      sum += a[i];
    }
    return sum;
  }

  function reservedArray() {
    var i = 0;
    var a = new Array(10000);
    for (i = 0; i < 10000; i++) {
      a[i] = i;
    }
    var sum = 0;
    var l = a.length;
    for (i = 0; i < l; i++) {
      sum += a[i];
    }
    return sum;
  }

  function reservedArrayWithProperty() {
    var i = 0;
    var a = new Array(10000);
    a.foo = 123;
    for (i = 0; i < 10000; i++) {
      a[i] = i;
    }
    var sum = 0;
    var l = a.length;
    for (i = 0; i < l; i++) {
      sum += a[i];
    }
    return sum;
  }

  function arrayWithProperty() {
    var i = 0;
    var a = [];
    a.foo = 123;
    for (i = 0; i < 10000; i++) {
      a[i] = i;
    }
    var sum = 0;
    var l = a.length;
    for (i = 0; i < l; i++) {
      sum += a[i];
    }
    return sum;
  }

  function objectWithProperty() {
    var i = 0;
    var a = {};
    a.foo = 123;
    for (i = 0; i < 10000; i++) {
      a[i] = i;
    }
    var sum = 0;
    var l = a.length;
    for (i = 0; i < l; i++) {
      sum += a[i];
    }
    return sum;
  }
</script>

Test runner

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plainArray();

objectWithProperty();

reservedArray();

arrayWithProperty();

reservedArrayWithProperty();

protoArray();

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Revisions

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:

• Revision 1: published by Erik Corry on 12th December 2012
• Revision 2: published on 12th December 2012
• Revision 3: published by Erik Corry on 13th December 2012

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