Object Cloning

clone.js

/**
 * Clones an object and retains the prototype chain
 * @param   {Object} fromObj Object to be cloned
 * @returns {Object} Cloned Object
 */
function cloneObj(fromObj) {
  var toObj, i;

  if (fromObj && typeof fromObj === 'object') {
    
    /** Creates a new instance of fromObj constructor */
    toObj = new fromObj.constructor();

    for (i in fromObj) {
      
      /** Copies only own property */
      if (fromObj.hasOwnProperty(i)) {
        toObj[i] = fromObj[i];
      }
      
    }
  } else {
    throw new Error(fromObj + ' cannot be cloned');
  }

  return toObj;
}

cloneexample.js

/**Example of using the cloneObj*/

/**
 * Profile Class
 * @param {String} name  Profile's name
 * @param {Number} age  Profile's age
 * @param {Function} toStringFn Overrides the toString function
 * @param {Object} father Father's profile
 */
var Profile = function (name, age, toStringFn, father) {
  this.name = name || 'NA';
  this.age = age;
  this.father = father || 'NA';
  this.toString = toStringFn;
};

/** Prototype functions */
Profile.prototype = {
  setName: function (name) {
    this.name = name;
  },
  setAge: function (age) {
    this.age = age;
  },
  setFather: function (father) {
    this.father = father;
  },
  getName: function () {
    return this.name;
  },
  getAge: function () {
    return this.age;
  },
  getFather: function () {
    return this.father;
  }
};

/** Resetting the constructor */
Profile.prototype.constructor = Profile;

/**Father's profile*/
var father = new Profile('George H.W. Bush', 92, function () {
  return 'Hello there... I\'m ' + this.name;
});

/**Son1's profile*/
var son1 = new Profile('George W. Bush', 62, function () {
  return 'Hey folks... You know me... I\'m ' + this.name;
}, father);

/**Son2 is clone of son 1*/
var son2 = cloneObj(son1);
son2.setName('Jeb Bush');

son1.getName(); // Outputs George W. Bush
son2.getName(); // Outputs Jeb Bush
son2.getFather().getName(); //Outputs George H.W. Bush