Array unshift vs prepend (v21)

Revision 21 of this benchmark created by Al on

Preparation HTML

<script>
  var a;
  var prependArray = function(value, oldArray) {
   var i, len = oldArray.length + 1,
       newArray = new Array(len);
   newArray[0] = value;
   for (i = 0; i < len; ++i) {
    newArray.push(oldArray[i]);
   }
   return newArray;
  }

  var prependArray2 = function(value, oldArray) {
   var i, len = oldArray.length + 1,
       newArray = new Array(len);
   newArray[0] = value;
   return newArray.concat(oldArray);
  }
</script>

Setup

a = [1, 2, 3, 4];

Test runner

Ready to run.

Testing in
TestOps/sec
Unshift
a.unshift(0);
ready
Prepend function
prependArray(0, a);
ready
Unshift without mutation
a.slice(0).unshift(0);
ready
splice
a.splice(0,0,0);
ready
Prepend2 function
prependArray2(0, a);
ready
push reverse
a.reverse();
a.push(0);
a.reverse();
ready

Revisions

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