clone.js

/**
    * Clone an object, contains fixes for the Radu Simionescu's clone function
    * http://stackoverflow.com/questions/728360/most-elegant-way-to-clone-a-javascript-object?page=2&tab=active#tab-top
    * @param {*} oReferance
    * @return {*}
    */
var clone = function(oReferance) {
  var aReferances = new Array();
  var getPrototypeOf = function(oObject) {
    if(typeof(Object.getPrototypeOf)!=="undefined")
      return Object.getPrototypeOf(oObject);

    var oTest = new Object();

    if(typeof(oObject.__proto__)!=="undefined" && typeof(oTest.__proto__)!=="undefined" && oTest.__proto__===Object.prototype)
      return oObject.__proto__;

    if(typeof(oObject.constructor)!=="undefined" && typeof(oTest.constructor)!=="undefined" && oTest.constructor===Object && typeof(oObject.constructor.prototype)!=="undefined")
      return oObject.constructor.prototype;

    return Object.prototype;
  };

  var recursiveCopy = function(oSource) {
    if(typeof(oSource)!=="object")
      return oSource;

    if(oSource===null)
      return null;

    for(var i = 0; i < aReferances.length; i++)
      if(aReferances[i][0]===oSource)
        return aReferances[i][1];

    if(Array.isArray(oSource)) {
      var oCopy = [];
      oCopy.prototype = getPrototypeOf(oSource);
      aReferances.push([oSource, oCopy]);

      for(var k in oSource)
        oCopy[k] = recursiveCopy(oSource[k]);
    } else {
      var Copy = new Function();
      Copy.prototype = getPrototypeOf(oSource);
      var oCopy = new Copy();
      aReferances.push([oSource,oCopy]);

      for(var sPropertyName in oSource) {
        if(oSource.hasOwnProperty(sPropertyName))
          oCopy[sPropertyName] = recursiveCopy(oSource[sPropertyName]);
      }
    }

    return oCopy;
  };
  
  return recursiveCopy(oReferance);
};

/* === Demo === */

var event = {date: '06/12/16', content: 'Eat some hamburger'}; // {... content: Go to school}
var copy1 = event;
var copy2 = clone(event);

copy1.content = 'Eat some cheese';
console.log(event.content); // 'Eat some cheese'

copy2.content = 'nothing';
console.log(event.content); // 'Eat some cheese', not modified because that's a clone