Primitive value string vs Wrapper Object String - length

JavaScript performance comparison

Revision 2 of this test case created by

Preparation code

str1.length = <div id="id1"></div><br>
str2.length = <div id="id2"></div>

Benchmark.prototype.setup = function() {
  var str11 = Math.random().toString();
  var str12 = Math.random().toString();
  var str21 = new String(str11);
  var str22 = new String(str12);
  var i = "(idle)",
      k = "(idle)";


Benchmark.prototype.teardown = function() {
  var x = document.getElementById("id1"); x.innerHTML = i;
  var y = document.getElementById("id2"); y.innerHTML = k;


Preparation code output

str1.length = <div id="id1"></div><br> str2.length = <div id="id2"></div>

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
Primitive value string str1.length
i = str11.length;
var tmp = str11; str11 = str12; str12 = tmp;
Wrapper object string str2.length
k = str21.length;
var tmp = str21; str21 = str22; str22 = tmp;

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str1.length =

str2.length =