Cloning an Object (v82)

Revision 82 of this benchmark created by atSetKey on

Description

There is no quick and easy facility for cloning an object, Some people recommend using JQuery.extend others JSON.parse/stringify

http://stackoverflow.com/questions/122102/what-is-the-most-efficient-way-to-clone-a-javascript-object

If you want the fastest possible clone function. I would personally anticipate the data structure of your object and write a custom clone to handle it.

Preparation HTML

<script src="http://code.jquery.com/jquery-2.0.3.js" type="text/javascript"></script>


<script>
  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;
  }
  
  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
   }
  });

//Crockford clone function
function object(o) {
    function F() {}
    F.prototype = o;
    return new F();
}
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
JQuery.extend deep
var newObject = jQuery.extend(true, {}, oldObject);
ready
JSON
var newObject = JSON.parse(JSON.stringify(oldObject));
ready
JQuery.extend
var newObject = jQuery.extend({}, oldObject);
ready
simple clone function
var newObject = clone(oldObject);
ready
ES5 Object.clone
var newObject = Object.clone(oldObject);
ready
Crockford Clone Function
var newObject = object(oldObject);
ready
    var newObject = {};
    for (var k in oldObject){
    newObject[k]=oldObject[k];   
    }
 
ready

Revisions

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