Fastest array loops in Javascript (v115)

Revision 115 of this benchmark created by Heavensrevenge on

Setup

// Populate the base array
  var arr = [];
  for (var i = 0; i < 1000; i++) {
    arr[i] = i;
  }
  
  function someFn(ix) {
    return ix << 1;
  }
  var len = arr.length, i = 0;

Test runner

Ready to run.

Testing in
TestOps/sec
For loop, basic
for (var i = 0; i < arr.length; i++) {
  someFn(arr[i]);
}
ready
While loop, basic
while (i < len) {
  someFn(arr[i]);
  i++;
}
ready
For loop, cached+init
for (var i = 0; i < len; i++) {
  someFn(arr[i]);
}
ready
For loop, i--
for (var i = len; i > 0; i--) {
  someFn(arr[i]);
}
ready
Do-while loop, i--
var i = len - 1;
do {
  someFn(arr[i]);
} while (i--);
ready
Do-while loop, --i
var i = len;
if (i > 0) {
  do {
    someFn(arr[i]);
  }
  while (--i);
}
ready
For..in loop
for (var i in arr) {
  someFn(arr[i]);
}
ready
Order
while (i = arr.shift()) {
  someFn(i);
}
ready
forEach
arr.forEach(function(v) {
  someFn(v)
})
ready
order validation
while ((i = arr.shift()) !== undefined) {
  someFn(i);
}
ready
While ! Undefined
var a;
while ((a = arr[i++]) !== undefined) {
  someFn(a);
}
ready
Pop
while ((i = arr.pop()) !== undefined) {
  someFn(i);
}
ready
Order w/ array copy
var copy = arr.slice(0);
while (i = copy.shift()) {
  someFn(i);
}
ready
While length--
var l = len;
while (l--) {
  someFn(arr[l]);
}
ready
pop2
while (i !== undefined) {
  someFn(i);
  i = arr.pop();
}
ready
non-init for
for (; i < len; ++i) {
  someFn(i);
}
ready
Object.keys
Object.keys(arr).forEach(function(i) {
	someFn(i);
});
ready

Revisions

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