array cloning

JavaScript performance comparison

Revision 139 of this test case created by John

Preparation code

<script src="">

Benchmark.prototype.setup = function() {
  var a = [{test: 'bye'}, 'z', 'a', 'q', 'w', 's', 'x', 'c', 'd', 'v', 'e', 'f', 't', 'r', 'g', 't', 'm', 'y', 'h', 't', 'y', 'j', 'i', 'o', 'l', 'f', 's', 'd', 'j', 'n', 'm', 'c', 'u', 'i', 'e', 'w', 'h', 'r', ',', 'w', 'e', 'n', 'r', 'w', 'n', 'e', 'b', 'f', '2', '3', '4', '2', '3', '4', 'n', 'j', 'm', 'f', 'd', 's', 'j', 'd', 'y', 'f', 'g', '2', '3', 'h', 'f', 's', 'j', 'd', 'b', 'm', 'f', 'h', 's', 'd', 'h', 'f', 'o', '2', '3', 'i', 'z', 'a', 'q', 'w', 's', 'x', 'c', 'd', 'v', 'e', 'f', 't', 'r', 'g', 't', 'm', 'y', 'h', 't', 'y', 'j', 'i', 'o', 'l', 'f', 's', 'd', 'j', 'n', 'm', 'c', 'u', 'i', 'e', 'w', 'h', 'r', ',', 'w', 'e', 'n', 'r', 'w', 'n', 'e', 'b', 'f', '2', '3', '4', '2', '3', '4', 'n', 'j', 'm', 'f', 'd', 's', 'j', 'd', 'y', 'f', 'g', '2', '3', 'h', 'f', 's', 'j', 'd', 'b', 'm', 'f', 'h', 's', 'd', 'h', 'f', 'o', '2', '3', 'i', 'z', 'a', 'q', 'w', 's', 'x', 'c', 'd', 'v', 'e', 'f', 't', 'r', 'g', 't', 'm', 'y', 'h', 't', 'y', 'j', 'i', 'o', 'l', 'f', 's', 'd', 'j', 'n', 'm', 'c', 'u', 'i', 'e', 'w', 'h', 'r', ',', 'w', 'e', 'n', 'r', 'w', 'n', 'e', 'b', 'f', '2', '3', '4', '2', '3', '4', 'n', 'j', 'm', 'f', 'd', 's', 'j', 'd', 'y', 'f', 'g', '2', '3', 'h', 'f', 's', 'j', 'd', 'b', 'm', 'f', 'h', 's', 'd', 'h', 'f', 'o', '2', '3', 'i'];
  var b = [];


Benchmark.prototype.teardown = function() {
  if (b.length !== a.length) {
    throw {message: "Test failed! b.length !== a.length"};
  b[0].test = 'hi';
  if (a[0].test === 'hi') {
  //  throw {message: "Not a deep clone"};
  for (var i = 1, l = a.length; i < l; i++) {
    if (b[i] !== a[i]) {
      throw {message: "Test failed! b array is " + b};


Preparation code output

Test runner

Warning! For accurate results, please disable Firebug before running the tests. (Why?)

Java applet disabled.

Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
backward while-loop
var i = a.length;
while(i > -1) { b[i] = a[i]; i--;}


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