get process list from guest

I'm trying to build a synchronous run program in guest (linux) since for some ridicules reason vRO doesn't provide this out of the box.  All I need to do is figure out how to check if the exitCode or endTime of a process is null/undefined and I can't seem to figure out what it wants.

The process list task returns an array of:

{pid:number, name:string, owner:string, cmdLine:string, startTime:Date, endTime:Date, exitCode:number}

If I iterate over the return value,  I can System.log(pid.exitCode) or pid[exitCode] and it says "__NULL__".  If I try and do something like: if (pid.exitCode === null) ... or undefined ... it tosses out this error code:

Invalid JavaScript value of type ch.dunes.model.type.TypeConverter$NullObject

How can I check to see if endTime or exitCode are populated?  once they have actual values I'll be able to assume the process has ended.