push allocated vs dynamic (v29)

Revision 29 of this benchmark created on

Description

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

Setup

var n = 10000;
    
    var myArray = [];
    
    var myArray2 = new Array(n);

Test runner

Ready to run.

Testing in
TestOps/sec
straight writing, pre-allocated in constructor
var i = 0;
while (i < n) {
  myArray2[i] = i;
  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--) {
   myArray2[i] = i
 }
ready
straight writing
var i = 0;
while (i < n) {
  myArray[i] = i;
  i++;
}
ready
straight writing, pre-allocated with []
n--;
myArray[n] = n;
n--;
var i = 0;
while (i < n) {
  myArray[i] = i;
  i++;
}
ready
push
for (var i = 0; i < n; i++) {
  myArray.push(i)
}
ready

Revisions

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