array.length vs. cached (v12)

Revision 12 of this benchmark created on

Setup

var a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
    a = a.concat(a, a, a, a, a, a, a, a);

Test runner

Ready to run.

Testing in
TestOps/sec
not-cached
(function(a) {
  var sum = 0;
  for (var i = 0; i < a.length; ++i) {
    sum += a[i];
  }
  return sum;
})(a);
ready
cached
(function(a) {
  var sum = 0;
  for (var i = 0, aLen = a.length; i < aLen; ++i) {
    sum += a[i];
  }
  return sum;
})(a);
ready
cached, decrement
(function(a) {
  var sum = 0;
  for (var i = a.length - 1; i--;) {
    sum += a[i];
  }
  return sum;
})(a);
ready
cached, decrement 2
(function(a) {
  var sum = 0;
  var len = a.length - 1;
  for (var i = len; --i;) {
    sum += a[i];
  }
  return sum;
})(a);
ready
decrement 3
(function(a) {
  var sum = 0;
  for (var i = a.length - 1; i >= 0; i--) {
    sum += a[i];
  }
  return sum;
})(a);
ready
decrement 4
(function(a) {
  var sum = 0;
  var i = a.length - 1;
  for (; i-- ;) {
    sum += a[i];
  }
  return sum;
})(a);
ready

Revisions

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