cloning an object

JavaScript performance comparison

Revision 116 of this test case created by

Preparation code

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>

      
<script>
Benchmark.prototype.setup = function() {
  var oldObject = {
    a: 1,
    b: 2,
    c: 3,
    d: 4,
    e: 5,
    f: function() {
      return 6;
    },
    g: [7, 8, 9]
  };
  
  
  function clone(obj) {
    var target = {};
    for (var i in obj) {
      if (obj.hasOwnProperty(i)) {
        target[i] = obj[i];
      }
    }
    return target;
  }
  
  function assign(obj) {
    return Object.assign({}, obj);
  }
  
  Object.defineProperties(Object, {
    'extend': {
      'configurable': true,
      'enumerable': false,
      'value': function extend(what, wit) {
        var extObj, witKeys = Object.keys(wit);
  
        extObj = Object.keys(what).length ? Object.clone(what) : {};
  
        witKeys.forEach(function(key) {
          Object.defineProperty(extObj, key, Object.getOwnPropertyDescriptor(wit, key));
        });
  
        return extObj;
      },
      'writable': true
    },
    'clone': {
      'configurable': true,
      'enumerable': false,
      'value': function clone(obj) {
        return Object.extend({}, obj);
      },
      'writable': true
    }
  });

};
</script>

Preparation code output

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
jQuery.extend() deep
var newObject = jQuery.extend(true, {}, oldObject);
pending…
JSON stringify/parse
var newObject = JSON.parse(JSON.stringify(oldObject));
pending…
jQuery.extend()
var newObject = jQuery.extend({}, oldObject);
pending…
clone function
var newObject = clone(oldObject);
pending…
ES5 Object.clone
var newObject = Object.clone(oldObject);
pending…
stringify eval
var newObject = eval("(" + JSON.stringify(oldObject) + ")");
pending…
Manual copy
newObject = {
  a: oldObject.a,
  b: oldObject.b,
  c: oldObject.c,
  d: oldObject.d,
  e: oldObject.e,
  f: oldObject.f,
  g: oldObject.g
};
pending…
No HasOwnCheck
newObject = {}
for (var i in oldObject) {
  newObject[i] = oldObject[i];
}
pending…
assign
var newObject = assign(oldObject);
pending…

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Revisions

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