cloning an object (v27)

Revision 27 of this benchmark created by fahsdf 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://cdnjs.cloudflare.com/ajax/libs/lodash.js/3.3.1/lodash.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) {
       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
       }
      });

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
lodash deep
var newObject = _.cloneDeep(oldObject)
ready
lodash shallow
var newObject = _.clone(oldObject)
ready

Revisions

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