for vs forEach (v414)

Revision 414 of this benchmark created by Amuseum on

Description

Is it faster to use the native forEach or just loop with for?

Preparation HTML

<script>
  var i, values = [],
      sum = 0;
  for (i = 0; i < 10000; i++) {
   values[i] = i;
  }
  
  function add(val) {
   sum += val;
  }
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
forEach
values.forEach(add);
ready
for loop, simple
for (i = 0; i < values.length; i++) {
  add(values[i]);
}
ready
for loop, cached length
var len = values.length;
for (i = 0; i < len; i++) {
  add(values[i]);
}
ready
for loop, reverse
for (i = values.length - 1; i >= 0; i--) {
  add(values[i]);
}
ready
forEach more local
(function() {
  var sum = 0;
  values.forEach(function(val) {
    sum += val;
  });
})();
ready
for loop, local vars
for (var i = 0, len = values.length; i < len; i++) {
  add(values[i]);
}
ready
for in
for (i in values) {
  add(values[i]);
}
ready
for of
for (i of values) {
  add(i);
}
ready
forEach anonymous
values.forEach(function(val) {
  sum += val;
});
ready
for loop, localize array
for (var i = 0, v = values, len = v.length; i < len; i++) {
  add(v[i]);
}
ready
map function
function map(array, func) {
  for (var i = 0, a = array, len = a.length; i < len; i++) {
    func(a[i]);
  }
}
map(values, add);
ready
map, local func
function map(array, func) {
  for (var i = 0, a = array, len = a.length, f = func; i < len; i++) {
    f(a[i]);
  }
}
map(values, add);
ready
array.reduce()
add = function(sum, addend) {
  return sum + addend;
}
sum = values.reduce(add);
ready
array.map
values.map(add);
ready
for loop, localize function
for (var i = 0, a = values, l = a.length, f = add; i < l; i++) {
  f(a[i]);
}
ready
pop
for (var i; i = values.pop();) sum += i
ready
pop function
for (var i; i = values.pop();) add(i)
ready
slice, pop
var b = values.slice()
for (var i; i = b.pop();) sum += i
ready
copy, pop
var b = [];
for (var i = 0, a = values, l = a.length; i < l; i++) {
  b[i] = a[i];
}
for (var i; i = b.pop();) sum += i
ready
map-pop
function mappop(array, func) {
  for (var i; i = array.pop();) func(i)
}
mappop(values, add);
ready
map-copy-reverse-pop
Array.prototype.copy = function() {
  var b = [];
  for (var i = 0, a = this, s = a.length; i < s; i++) {
    b[i] = a[i];
  }
  return b;
};

function mappop(array, func) {
  var b = [];
  var c = array.copy().reverse();
  for (var i, a = array, f = func; i = a.pop();) f(i)
}
mappop(values, add);
ready
mappop - f.call
Array.prototype.copy = function() {
  var b = [];
  for (var i = 0, a = this, s = a.length; i < s; i++) {
    b[i] = a[i];
  }
  return b;
};

function mappop(array, func) {
  var b = [];
  var c = array.copy().reverse();
  for (var i, a = array, f = func; i = a.pop();) f.call(null, i)
}
mappop(values, add);
ready

Revisions

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