Loops - store length

Benchmark created by yotam on

Preparation HTML

<script>
  function bar(item) {};
  var values = [];
  for (var a = 0; a < 10000; a++) {
    values[a] = a;
  }
  var len = values.length;
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
For Unoptimized
for (var i = 0; i < values.length; i++) {
  bar(values[i]);
}
ready
For Optimized
// for loop:
for (var i = 0; i < len; i++) {
  bar(values[i]);
}
ready
do-while unoptimized
var j = 0;
do {
  bar(values[j++]);
} while (j < values.length);
ready
do-while optimized
var j = 0;
do {
  bar(values[j++]);
} while (j < len);
ready
while unoptimized
var k = 0;
while (k < values.length) {
  bar(values[k++]);
}
ready
while optimized
var k = 0;
while (k < len) {
  bar(values[k++]);
}
ready
For Optimized 2
for (var i = len; i--;) {
  bar(values[i]);
}
ready
do-while optimized 2
var j = len - 1;
do {
  bar(values[j]);
} while (j--);
ready
while optimized 2
var k = len;
while (k--) {
  bar(values[k]);
}
ready

Revisions

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