js-object-III.js

const createUser = (firstName, lastName) => {
      const user = {};
      user.firstName = firstName;
      user.lastName = lastName;

      merge(user, methods);

      return user;
    }

    const methods = {
      sayHello: function() {
        console.log(`Hello ${this.firstName} ${this.lastName}`);
      }
    }

    const merge = function(obj, methods) {
      for (const key in methods) {
        obj[key] = methods[key];
      }
    }

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