arrays - Set object property javascript -

i not sure possible guys can it:

 var tricky = function(obj){  var ret = new object();  ret.porp1 = 'undefined';  ret.prop2 = 'undefined';  (porp in ret){     if (obj.hasownproperty(prop) == false){         obj.???????? = prop;  }  return obj;  }   tricky({prop1:'ok_prop'});   ===>>{prop1:'ok_prop',prop2:'undefined'} 

i did not put question in words because find hard define properly. problem can see: have object , set properties in object not. want function check if object has range of properties , if not set explicitly undefined. not work if leave implicitly undefined, since use send jade template might have property set value system has changed state , want undefined.

what should put after obj.[what put here] set @ first porp1 prop2.

i assuming want add members of "template" object ret obj if not exist & porp typo.

you if not exist want set explicitly undefined there no need non-existent member of object undefined:

 var x = new object();   alert (typeof x.wibble === 'undefined') //true 

your ret.porp1 = 'undefined'; assigning string object textual content 'undefined' member, has nothing state of being "undefined", if intention:

var tricky = function(obj) {     var ret = {         prop1: 'undefined',         prop2: 'undefined'     }     (requiredmember in ret) {         if (obj.hasownproperty(requiredmember) === false) {             obj[requiredmember] = ret[requiredmember];         }     }     return obj; }  var o = {prop1:'ok_prop'};  o = tricky(o);  console.dir(o);   object     prop1: "ok_prop"     prop2: "undefined"