gistfile1.txt

const obj4 ={
  firstName:'nikhil',
  lastName:'karkra',
  isTeaching: true,
  greet:function(){
     console.log("hi")
  },
  address:{
    city:'Melbourne'
  }
}

const newObj = {...obj4, address:{city:'new city'}}

console.log(newObj.address.city) // "new city"
console.log(obj4.address.city) // "Melbourne"