@@ -0,0 +1,126 @@
+import { isDuplicate, isEveryInclude, isMoreThanLimit, isNotMatchRegex, isSomeNotInclude } from '../util/index.js';
+import { LIMIT_ORDER_COUNT, MENU_CATEGORIES, MENUS, ORDER_REGEX } from '../constant/index.js';
+
+const ERROR_MESSAGE = Object.freeze({
+    INVALID_DATE: '유효하지 않은 날짜입니다. 다시 입력해 주세요.',
+    IS_INVALID_ORDER: '유효하지 않은 주문입니다. 다시 입력해 주세요.',
+});
+
+const { INVALID_DATE, IS_INVALID_ORDER } = ERROR_MESSAGE;
+
+class Order {
+    static validateOrder(orderMenus) {
+        const validators = [
+            () => Order.validateDuplicationOrder(orderMenus),
+            () => Order.validateOrderMenuFormat(orderMenus, ORDER_REGEX.ORDER_FORMAT),
+            () => Order.validateLimitOrderCount(orderMenus, LIMIT_ORDER_COUNT),
+            () => Order.validateIncludeMenu(orderMenus, MENUS),
+            () => Order.validateOrderOnlyOneCategory(orderMenus, MENUS, MENU_CATEGORIES.BEVERAGE),
+        ];
+
+        validators.forEach((validator) => validator());
+    }
+    static validateDate(date) {
+        const validators = [() => Order.validateDayFormat(date, ORDER_REGEX.DAY_FORMAT)];
+
+        validators.forEach((validator) => validator());
+    }
+    static validateOrderOnlyOneCategory(orderMenus, menus, category) {
+        const { orderMenuNameList } = Order.parseOrders(orderMenus);
+        const menuNameListForCategory = Object.values(menus)
+            .filter((menu) => menu.CATEGORY === category)
+            .map((menu) => menu.NAME);
+
+        isEveryInclude(IS_INVALID_ORDER, orderMenuNameList, menuNameListForCategory);
+    }
+    static validateIncludeMenu(orderMenus, menus) {
+        const { orderMenuNameList } = Order.parseOrders(orderMenus);
+        const menuNameList = Object.values(menus).map((menu) => menu.NAME);
+
+        isSomeNotInclude(IS_INVALID_ORDER, orderMenuNameList, menuNameList);
+    }
+    static validateDuplicationOrder(orderMenus) {
+        const { orderMenuNameList } = Order.parseOrders(orderMenus);
+
+        isDuplicate(IS_INVALID_ORDER, orderMenuNameList);
+    }
+    static validateLimitOrderCount(orderMenus, limitOrderCount) {
+        const { totalOrderCount } = Order.parseOrders(orderMenus);
+
+        isMoreThanLimit(IS_INVALID_ORDER, totalOrderCount, limitOrderCount);
+    }
+    static validateOrderMenuFormat(orderMenus, regex) {
+        const { orderMenuList } = Order.parseOrders(orderMenus);
+
+        orderMenuList.forEach((orderMenu) => isNotMatchRegex(IS_INVALID_ORDER, orderMenu, regex));
+    }
+    static validateDayFormat(date, regex) {
+        isNotMatchRegex(INVALID_DATE, date, regex);
+    }
+    static parseOrders(orderMenu) {
+        const orderMenuList = orderMenu.split(',').map((menu) => menu.trim());
+        const orderMenuNameList = orderMenuList.map((menu) => menu.split('-')[0]);
+        const orderMenuCountList = orderMenuList.map((menu) => menu.split('-')[1]);
+        const totalOrderCount = orderMenuCountList.reduce((acc, cur) => acc + Number(cur), 0);
+
+        return {
+            orderMenuList,
+            orderMenuNameList,
+            orderMenuCountList,
+            totalOrderCount,
+        };
+    }
+
+    #orderDate;
+    #orderMenus = new Map();
+    #menus = new Map();
+
+    constructor(menus, orderMenus, orderDate) {
+        this.#menus = new Map(Object.entries(menus));
+        this.#orderDate = orderDate;
+        this.#setOrderMenus(orderMenus);
+    }
+
+    getOrderMenuList() {
+        return this.#getOrderMenuCategories()
+            .map((categoryName) => this.getOrderMenuByCategory(categoryName))
+            .flat();
+    }
+    getTotalPrice() {
+        return Array.from(this.#orderMenus.values()).reduce((acc, orderMenu) => {
+            const key = this.#getKeyByMenuName(orderMenu.name);
+            const menu = this.#menus.get(key);
+            return acc + menu.PRICE * orderMenu.count;
+        }, 0);
+    }
+    getOrderDate() {
+        return this.#orderDate;
+    }
+    getOrderMenuByCategory(categoryName) {
+        return Array.from(this.#orderMenus.values()).filter((orderMenu) => orderMenu.category === categoryName);
+    }
+    #setOrderMenus(orderMenus) {
+        const { orderMenuNameList, orderMenuCountList } = Order.parseOrders(orderMenus);
+
+        orderMenuNameList.forEach((menuName, index) => {
+            const category = this.#getCategoryByMenuName(menuName);
+            const key = this.#getKeyByMenuName(menuName);
+
+            this.#orderMenus.set(key, {
+                name: menuName,
+                count: orderMenuCountList[index],
+                category,
+            });
+        });
+    }
+    #getOrderMenuCategories() {
+        return Array.from(new Set(Array.from(this.#menus.values()).map((menu) => menu.CATEGORY)));
+    }
+    #getCategoryByMenuName(menuName) {
+        return Array.from(this.#menus.values()).find((menuMap) => menuMap.NAME === menuName).CATEGORY;
+    }
+    #getKeyByMenuName(menuName) {
+        return Array.from(this.#menus.keys()).find((key) => this.#menus.get(key).NAME === menuName);
+    }
+}
+export default Order;

리뷰: 배열, Map, 객체의 여러가지 메서드들을 잘 활용하시는 것 같아요.
배워갑니다!