var userInfo = {
  name: "Mayank",
  age: 31,
  designation: "Developer",
  address: {
    streetNumber: 10,
    city: "Delhi",
    country: "India"
  }
}

var stringifiedObject = JSON.stringify(userInfo);

var newDeepCopy = JSON.parse(stringifiedObject);

console.dir(newDeepCopy)