Iterator pattern

interface Iterator {
  next(): Object;
  hasNext(): boolean;
}

class DinnerMenuIterator implements Iterator {
  items: MenuItem[];
  position: number = 0;

  constructor(items: MenuItem[]) {
    this.items = items;
  }

  next(): MenuItem {
    const menuItem = this.items[this.position];
    this.position++;
    return menuItem;
  }

  hasNext(): boolean {
    if (this.position >= this.items.length || this.items[this.position] === undefined) {
      return false;
    } else {
      return true;
    }
  }
}

class BreakfastMenuIterator implements Iterator {
  items: Map;
  position: number = 0;

  constructor(items: Set<MenuItem>) {
    this.items = items;
  }

  next(): MenuItem {
    const menuItem = this.items.get(this.position);
    this.position++;
    return menuItem;
  }

  hasNext(): boolean {
    if (this.position >= this.items.size || this.items.get(this.position) === undefined) {
      return false;
    } else {
      return true;
    }
  }
}

class MenuItem {
  name: string;
  description: string;
  vegeterian: boolean;
  price: number;

  constructor(name: string, description: string, vegeterian: boolean, price: number) {
    this.name = name;
    this.description = description;
    this.vegeterian = vegeterian;
    this.price = price;
  }

  getName(): string {
    return this.name;
  }

  getPrice(): number {
    return this.price;
  }

  getDescription(): string {
    return this.description;
  }

  isVegeterian(): boolean {
    return this.vegeterian;
  }
}

class DinnerMenu {
  static MAX_ITEMS = 6;
  numberOfItems: number = 0;
  menuItems: MenuItem[];

  constructor() {
    this.menuItems = [];
    this.addItem("Rice", "Our classical rice with soy sauce", true, 2.45);
    this.addItem("Soup", "Noodle soup", true, 2.99);
    this.addItem("Porrage", "Porrage with beef", false, 5.19);
    this.addItem("Potatoe", "Fried potatoe with ketchup and burger", false, 4.99);
  }

  addItem(name: string, description: string, vegeterian: boolean, price: number) {
    const menuItem = new MenuItem(name, description, vegeterian, price);
    
    if (this.numberOfItems >= DinnerMenu.MAX_ITEMS) {
      console.log("Sorry, but menu is full. Can't add new item in menu");
    } else {
      this.menuItems.push(menuItem);
      this.numberOfItems++;
    }
  }

  createIterator(): Iterator {
    return new DinnerMenuIterator(this.menuItems);
  }
}

class PancakeHouseMenu {
  menuItems: Map;

  constructor() {
    this.menuItems = new Map();

    this.addItem("Regular pancake", "Our classical pancake with sourcream", true, 2.99);
    this.addItem("Sweet pancake", "Sweet pancake with berry jam", true, 1.99);
    this.addItem("Double breakfast", "Our classical pancake with fried potatoe and eggs", false, 4.99);
    this.addItem("Pancake fest", "Three types of our pancakes", true, 3.99);
  }

  addItem(
    name: string,
    description: string,
    vegeterian: boolean,
    price: number
  ) {
    const menuItem = new MenuItem(name, description, vegeterian, price);
    this.menuItems.set(this.menuItems.size, menuItem);
  }
  
  createIterator(): Iterator {
    return new BreakfastMenuIterator(this.menuItems);
  }
}

class Waitress {
  pancakeHouseMenu: PancakeHouseMenu;
  dinnerMenu: DinnerMenu;

  constructor(pancakeHouseMenu: PancakeHouseMenu, dinnerMenu: DinnerMenu) {
    this.pancakeHouseMenu = pancakeHouseMenu;
    this.dinnerMenu = dinnerMenu;
  }
  
  public printMenu() {
    const pancakeIterator = this.pancakeHouseMenu.createIterator();
    const dinnerIterator = this.dinnerMenu.createIterator();

    console.log('Breakfast menu:');
    this.getMenuItems(pancakeIterator);
    console.log('Dinner menu:');
    this.getMenuItems(dinnerIterator);
  }

  private getMenuItems(iterator: Iterator) {
    while(iterator.hasNext()) {
      const menuItem = iterator.next();
      console.log(`${menuItem.name}: ${menuItem.description}, ${menuItem.price}`);
    }
  }
}

const pancakes = new PancakeHouseMenu();
const dinners = new DinnerMenu();
const waitress = new Waitress(pancakes, dinners);

waitress.printMenu();