gistfile1.txt

function deepCopy(obj){
 const keys = Object.keys(obj)
 const newObject={}
 for(let i=0;i<keys.length;i++){
   const key = keys[i]
   if((!!obj[key]) && (obj[key].constructor === Object)){
      newObject[key] = deepCopy(obj[key])
    } else {
      newObject[key] = obj[key] 
    }  
  }
 return newObject
}

const obj4 ={
  firstName:'nikhil',
  lastName:'karkra',
  isTeaching: true,
  address:{
    state:'victoria',
    city:'Melbourne'
  }
}

const obj5 = deepCopy(obj4)

obj5.address.city="new city"

console.log(obj4.address.city) // Melbourne
console.log(obj5.address.city) // new city