Fastest array loops in Javascript (v167)

Revision 167 of this benchmark created on

Setup

// Populate the base array
  
  
  function someFn(ix) {
    return ix * 5 + 1 / 3 * 8;
  }

Test runner

Ready to run.

Testing in
TestOps/sec
For loop, basic
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
for (var i = 0; i < arr.length; i++) {
  someFn(arr[i]);
}
ready
While loop, basic
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
var i = 0;
while (i < arr.length) {
  someFn(arr[i]);
  i++;
}
ready
For loop, cached
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
for (var i = 0, len = arr.length; i < len; i++) {
  someFn(arr[i]);
}
ready
For loop, i--
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
for (var i = arr.length; i > 0; i--) {
  someFn(arr[i]);
}
ready
Do-while loop, i--
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
var i = arr.length - 1;
do {
  someFn(arr[i]);
}
while (i--);
ready
Do-while loop, --i
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
var i = arr.length;
if (i > 0) {
  do {
    someFn(arr[i]);
  }
  while (--i);
}
ready
For..in loop
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
for (var i in arr) {
  someFn(arr[i]);
}
ready
Order
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
while (i = arr.shift()) {
  someFn(i);
}
ready
forEach
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
arr.forEach(function(v) {
  someFn(v)
})
ready
order validation
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
while ((i = arr.shift()) !== undefined) {
  someFn(i);
}
ready
While ! Undefined
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
var a;
while ((a = arr[i++]) !== undefined) {
  someFn(a);
}
ready
Pop
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
while (i = arr.pop()) {
  someFn(i);
  newArr.push(i);
}
ready
Order w/ array copy
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
var copy = arr.slice(0);
while (i = copy.shift()) {
  someFn(i);
}
ready
Pop w/ reverse()
var arr = [],
  newArr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
arr.reverse();
while (i = arr.pop()) {
  someFn(i);
  newArr.push(i);
}
ready

Revisions

You can edit these tests or add more tests to this page by appending /edit to the URL.