js-object-V.js

    const User = function(firstName, lastName) {
      this.fistName = firstName;
      this.lastName = lastName;
    }

    User.prototype.sayHello = function() {
      console.log(`Hello ${this.firstName} ${this.lastName}`);
    }

    const user1 = new User('Erdem', 'Uslu');
    const user2 = new User('John', 'Smith');