push allocated vs dynamic (v46)

Revision 46 of this benchmark created by Mark on

Description

is it usefull to pre-allocate the array by setting the last value first when assigning some values ?

Preparation HTML

<script>
console.log('lol');
</script>

Setup

var n = 10000;
    var myArray = [];

Test runner

Ready to run.

Testing in
TestOps/sec
push
for (var i = 0; i < n; i++) {
  myArray.push(i)
}
ready
reverse writing
  var i = n;
  while (i--) {
    myArray[i] = i
  }
ready
reverse writing, array allocated with Array constructor
  var i = n;
  while (i--) {
    myArray[i] = i
  }
ready
auto incr
var i = n;
while (i--) {
  myArray[myArray.length] = i
}
ready
auto incr + forward
var i;
for (i = 0; i < n; i++) {
  myArray[myArray.length] = i
}
ready
auto incr + forward + extra cnt
var i, j = 0;
for (i = 0; i < n; i++) {
  myArray[j++] = i;
}
ready
p
var i, j = 0;
var arr = new Array(n);

for (i = 0; i < n; i++) {
  arr[i] = i;
}
ready

Revisions

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