Fastest array loops in Javascript (v39)

Revision 39 of this benchmark created by snekse on

Preparation HTML

<script>
  // Populate the base array
  var arr = [];
  for( var i = 0; i < 1000; i++ ) {
    arr[i] = 'value' + i;
  }

  function someFn (ix) {
      return ix * 5 + 1 / 3 * 8;
  }
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
For loop, basic
for( var i = 0; i < arr.length; i++ ) {
    someFn(i);
}
ready
While loop, basic
var i=0;
while(i < arr.length) {
    someFn(i);
    i++;
}
ready
For loop, cached
for (var i = 0, len = arr.length; i < len; i++) {
    someFn(i);
}
ready
For loop, i--
for (var i = arr.length; i > 0; i--) {
    someFn(i);
}
ready
Do-while loop, i--
var i = arr.length - 1;
do
{
    someFn(i);
}
while (i--);
ready
Do-while loop, --i
var i = arr.length;
if (i > 0)
{
    do
    {
        someFn(i);
    }
    while (--i);
}
ready
For loop, i--, 2 args
for (var i = arr.length; i--;) {
    someFn(i);
}
ready
while, i--, truthy i
var i = arr.length;
while (i--) {
  someFn(i);
};
ready
For loop, i--, truthy i
for (var i = arr.length; i; i--) {
    someFn(i);
}
ready

Revisions

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