text: function PersonName(firstName, lastName) { 
      this.firstName = firstName; 
      this.lastName = lastName;
   } 
  
  PersonName.prototype.fullName = function(){
      return [this.firstName, this.lastName].join(" ");
  }
  
  let pName1 = new PersonName("Gaurav", "Mehla");
  let pName2 = new PersonName("Sarthak", "Sharma");
  
  console.log( pName1.fullName() );
  console.log( pName2.fullName() );