node.js正确扩展json对象

Question

I'm currently using node-ews in a project to access an Exchange Web Server via node.js. Now i ran into a weird problem. To run for example a "CreateItem" request, which can be an E-Mail or Appointment for example, I'm giving the function the arguments as a json similar to this

var args = {
    "attributes" : {
        "SendMeetingInvitations" : "SendToAllAndSaveCopy"
    },
    "SavedItemFolderId": {
        "DistinguishedFolderId": {
            "attributes": {
                "Id": "calendar"
            }
        }
    },
    "Items" : {
        "CalendarItem" : {
            "Subject" : "",
            "Body" : {
                "attributes" : {
                },
                "$value" : ""
            },
            "ReminderIsSet" : "true",
            "ReminderMinutesBeforeStart" : "30",
            "Start" : "",
            "End" : "",
            "IsAllDayEvent" : "false",
            "LegacyFreeBusyStatus" : "Busy",
            "Location" : ""
        }
    }
};

As the REST-API I'm writing will receive Attributes like Subject, Start, End etc. I initially stripped out those out of the JSON and would define them later like

args.Items.CalendarItem.Subject = req.body.Subject;

Oddly this will make the internal validation of node-ews fail and tell me that CalendarItem has an invalid Child Subject. If i leave Subject als an empty string in the initial args and later change it set it to req.body.Subject it works just fine.

My question is this: Is the Object somewhat different if I later add attributes and if yes is there a way to do it right? Because I don't think its the best way to have a bunch of empty Attributes in my Object if they aren't used and define standard values for all of them even if api won't require them to be sent.

Would great if someone knew the answer. Hope i could clarify what the problem is

Answer 1

Ok,

so the problem seems to be this. Internally the JSON "object" seems to have an order based on the order the variable is defined. in JavaScript this is no problem. But when the xml is parsed, the tag that was defined last will also be at the end of the xml so if you had

   <someTag>
     <variable2 />
     <variable3 />
   </someTag>

and you add variable1 to your json by someTag.variable1 = x in the end the xml will look like this after beeing parsed by node-ews

   <someTag>
     <variable2 />
     <variable3 />
     <variable1 >x</variable1>
   </someTag>

Now unfortunately the exchange web server seems to be picky about the order of the xml tags. so when you build your json be sure to use the direct order. Changing content of the json later will not affect the order.