How to check if Given Object list is empty or not in Ecmascript without any inbuilt method

Question

How can I check if given student.data.subId.dataName is empty or not without using any inbuilt method or library, isEmpty or Object.keys or hasOwnProperty not working in Apache Nifi ExecuteScript's EcmaScript.

Hence I need it in very basic way how can I check if given data is wmpty or not.

I need to check if student.data.subId.dataName is empty or not(in this case it is empty)

const student={
  "status" : "success",
  "data" : {
    "noMoreWork" : 0,
    "subId" : {
      "labelName" : "",
      "dataName" : {
      }
    },
   restflow=[]
  }
}