cloning an object (v11)

Revision 11 of this benchmark created 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="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.0/angular.min.js"></script>

Setup

var oldObject = {
       a: 1,
       b: 2,
       c: 3,
       d: 4,
       e: 5,
       f: function() {
        return 6;
       },
       g: [7, 8, 9]
      };
      
      
      function clone(obj) {
     if(typeof obj === 'object') {
        var copy = {};
        for (var key in obj) {
          if (obj.hasOwnProperty(key)) {
            copy[key] = clone(obj[key]);
          }
        }
        return copy;
      }
      return 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
       }
      });

Test runner

Ready to run.

Testing in
TestOps/sec
jQuery.extend() deep
var newObject = jQuery.extend(true, {}, oldObject);
ready
JSON stringify/parse
var newObject = JSON.parse(JSON.stringify(oldObject));
ready
jQuery.extend()
var newObject = jQuery.extend({}, oldObject);
ready
clone function
var newObject = clone(oldObject);
ready
ES5 Object.clone
var newObject = Object.clone(oldObject);
ready
stringify eval
var newObject = eval("("+JSON.stringify(oldObject)+")");
ready
Angular copy
var newObject =  angular.copy(oldObject);
ready

Revisions

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