Loops (v205)

Revision 205 of this benchmark created by Ben N on

Preparation HTML

<script>
   var i,
        arr = [],
        sum = 0
    
    
    for (i = 0; i < 10000; i++) {
        arr[i] = Math.random();
    }
</script>

Setup

Array.prototype.my_forEach = function(f) {
      for (var k = -1, m = this.length; ++k < m;)
        if (k in this) f(this[k], k, this)
    }
    
    var my_forEach = function(A, f) {
      for (var k = 0, m = A.length; k < m; k++)
        if (k in A) f(A[k], k, A)
    }

Test runner

Ready to run.

Testing in
TestOps/sec
while loop that imitates a for loop
var i = 0;
while (i < arr.length) {
  sum += arr[i];
  i++;
};
ready
while loop that imitates a for loop, caching the length
var i = 0,
  len = arr.length;
while (i < len) {
  sum += arr[i];
  i++;
};
ready
Reverse while loop
var i = arr.length;
while (i--) {
  sum += arr[i];
};
ready
Reverse while loop without implicit ToBoolean
var i = arr.length;
while (i-- > 0) {
  sum += arr[i];
};
ready
Reverse do … while loop
function wi(arr, cb) {
  var i = arr.length;
  while (i-- > 0) {
    cb(arr[i]);
  };
}

wi(arr, function(x) {
  x;
});
ready
Reverse for loop
for (var i = arr.length; i--;) {
  sum += arr[i];
};
ready
Old ’n’ busted for loop
function foreach(array, cb) {
  var i = 0,
    len = array.length;

  for (; i < len; ++i) cb(array[i]);
}

foreach(arr, function(x) {
  x;
})
ready
Old ’n’ busted for loop, caching the length
for (var i = 0, len = arr.length; i < len; ++i) {
  sum += arr[i];
};
ready
Cool guy loop
for (var i = -1; ++i < arr.length;) {
  sum += arr[i];
};
ready
Cool guy loop, caching the length
for (var i = -1, len = arr.length; ++i < len;) {
  sum += arr[i];
};
ready
Native Array#forEach implementation
arr.forEach(function(x) {
  sum += x;
});
ready
Native Array#forEach implementation with named function
function foo(x) {
  sum += x;
};
arr.forEach(foo);
ready
perso implement
arr.my_forEach(function(x) {
  sum += x;
});
ready
perso2
my_forEach(arr, function(x) {
  sum += x;
});
ready
Recursion with shift
function loop(x) {
  sum += x.shift();
  if (x.length != 0) loop(x);
}
loop(arr);
ready
Recursion with pop
function loop(x) {
  sum += x.pop();
  if (x.length != 0) loop(x);
}
loop(arr);
ready
Closure recursion with shift
function loop() {
  sum += arr.shift();
  if (arr.length != 0) loop();
}
loop();
ready
Closure recursion with pop
function loop() {
  sum += arr.pop();
  if (arr.length != 0) loop();
}
loop();
ready

Revisions

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