Helper Functions

Reservation Management

createUniqueReservationId()

Generates a unique reservation ID using a timestamp and random number. Signature:

function createUniqueReservationId(): string

Returns: A unique reservation ID in the format RES-{timestamp}-{random} Purpose: Creates a unique identifier for new reservations by combining the current timestamp (with special characters removed) and a random number between 0-99. Example:

import { createUniqueReservationId } from './utils/utils.js'

const reservationId = createUniqueReservationId()
console.log(reservationId) // "RES-20260303T120530123456Z-42"

getReservationById()

Retrieves a reservation by its ID. Signature:

function getReservationById(hotel, reservationId): Reservation | undefined

hotel

Hotel

required

The hotel object containing the reservations array

reservationId

string

required

The unique reservation ID to search for

return

Reservation | undefined

The reservation object if found, otherwise undefined

Example:

import { getReservationById } from './utils/utils.js'

const reservation = getReservationById(hotel, 'RES-20260303T120530123456Z-42')
if (reservation) {
  console.log(reservation.guest.name)
}

archiveReservation()

Moves a reservation from the active reservations list to the history. Signature:

function archiveReservation(hotel, reservation): void

hotel

Hotel

required

The hotel object to modify

reservation

Reservation

required

The reservation to archive

Purpose: Transfers a reservation to the hotel’s history array and removes it from the active reservations. Used when a reservation is completed or needs to be archived. Example:

import { archiveReservation, getReservationById } from './utils/utils.js'

const reservation = getReservationById(hotel, 'RES-123')
archiveReservation(hotel, reservation)
// Reservation is now in hotel.history and removed from hotel.reservations

createInvoice()

Creates an invoice object for a reservation. Signature:

function createInvoice(hotel, reservation): Invoice

hotel

Hotel

required

The hotel object

reservation

Reservation

required

The reservation to create an invoice for

return

Invoice

Invoice object with the following structure:

reservationId: The reservation ID
guest: Guest information
room: Object with room number and type
checkIn: Check-in date
checkOut: Check-out date
price: Object with room price, extras price, and total
emisionDate: Invoice emission date

Example:

import { createInvoice, getReservationById } from './utils/utils.js'

const reservation = getReservationById(hotel, 'RES-123')
const invoice = createInvoice(hotel, reservation)

console.log(invoice)
// {
//   reservationId: 'RES-123',
//   guest: { name: 'John Doe', ... },
//   room: { number: 101, type: 'double' },
//   checkIn: '2026-03-10',
//   checkOut: '2026-03-15',
//   price: {
//     room: 500,
//     extras: 50,
//     total: 550
//   },
//   emisionDate: '2026-03-03'
// }

getCancellationCharge()

Calculates the cancellation penalty based on how close to check-in the cancellation occurs. Signature:

function getCancellationCharge(reservation): number | undefined

reservation

Reservation

The reservation to calculate cancellation charge for

return

number | undefined

The cancellation charge amount based on the cancellation policy:

Less than 3 days before check-in: 100% of total price
3-7 days before check-in: 50% of total price
8 or more days before check-in: No charge (0)
Returns undefined if reservation is undefined

Example:

import { getCancellationCharge } from './utils/utils.js'

const charge = getCancellationCharge(reservation)
console.log(charge) // 250 (50% charge if 5 days before check-in)

The cancellation policy applies progressive penalties:

8+ days before: Free cancellation
3-7 days before: 50% charge
Less than 3 days: Full charge

Room Management

getRoomByNumber()

Retrieves a room by its room number. Signature:

function getRoomByNumber(hotel, roomNumber): Room | undefined

hotel

Hotel

required

The hotel object containing the rooms array

roomNumber

number

required

The room number to search for

return

Room | undefined

The room object if found, otherwise undefined

Example:

import { getRoomByNumber } from './utils/utils.js'

const room = getRoomByNumber(hotel, 101)
console.log(room.type) // "double"

getRoomsByStatus()

Filters rooms by their current status. Signature:

function getRoomsByStatus(rooms, status): Room[]

rooms

Room[]

required

Array of room objects to filter

status

string

required

The status to filter by (e.g., ‘available’, ‘occupied’, ‘maintenance’)

return

Room[]

Array of rooms matching the specified status

Example:

import { getRoomsByStatus } from './utils/utils.js'
import { ROOM_STATUS } from './utils/constants.js'

const availableRooms = getRoomsByStatus(hotel.rooms, ROOM_STATUS.AVAILABLE)
console.log(availableRooms.length) // Number of available rooms

getRoomsByType()

Filters rooms by their type. Signature:

function getRoomsByType(rooms, type): Room[]

rooms

Room[]

required

Array of room objects to filter

type

string

required

The room type to filter by (e.g., ‘single’, ‘double’, ‘suite’)

return

Room[]

Array of rooms matching the specified type

Example:

import { getRoomsByType } from './utils/utils.js'
import { ROOM_TYPE } from './utils/constants.js'

const suites = getRoomsByType(hotel.rooms, ROOM_TYPE.SUITE)
console.log(suites) // All suite rooms

isRoomAvailable()

Checks if a specific room is available for a given date range. Signature:

function isRoomAvailable(hotel, checkIn, checkOut, roomNumber): boolean

hotel

Hotel

required

The hotel object

checkIn

Temporal.PlainDate

required

The check-in date

checkOut

Temporal.PlainDate

required

The check-out date

roomNumber

number

required

The room number to check

return

boolean

True if the room is available for the date range, false if already reserved

Purpose: Checks if a room number is among the reserved rooms for a specific date range by comparing against confirmed reservations. Example:

import { isRoomAvailable } from './utils/utils.js'

const available = isRoomAvailable(
  hotel,
  Temporal.PlainDate.from('2026-03-10'),
  Temporal.PlainDate.from('2026-03-15'),
  101
)

if (available) {
  console.log('Room 101 is available for these dates')
}

getReservedRoomsByDate()

Retrieves all reserved room numbers for a specific date range. Signature:

function getReservedRoomsByDate(hotel, checkIn, checkOut): Set<number>

hotel

Hotel

required

The hotel object

checkIn

Temporal.PlainDate

required

The check-in date

checkOut

Temporal.PlainDate

required

The check-out date

return

Set<number>

A Set of room numbers that are reserved for the date range

Purpose: Filters confirmed reservations and identifies which room numbers have overlapping dates with the specified range. Example:

import { getReservedRoomsByDate } from './utils/utils.js'

const reservedRooms = getReservedRoomsByDate(
  hotel,
  Temporal.PlainDate.from('2026-03-10'),
  Temporal.PlainDate.from('2026-03-15')
)

console.log(reservedRooms) // Set { 101, 105, 203 }

getReservedRoomByRoomNumber()

Retrieves the room object for a given reservation. Signature:

function getReservedRoomByRoomNumber(hotel, reservation): Room | undefined

hotel

Hotel

required

The hotel object

reservation

Reservation

required

The reservation containing the room number

return

Room | undefined

The room object associated with the reservation

Example:

import { getReservedRoomByRoomNumber } from './utils/utils.js'

const room = getReservedRoomByRoomNumber(hotel, reservation)
console.log(room.number) // 101

Pricing Functions

getNumberOfNights()

Calculates the number of nights between two dates. Signature:

function getNumberOfNights(checkInString, checkOutString): number

checkInString

string | Temporal.PlainDate

required

The check-in date (ISO string or PlainDate object)

checkOutString

string | Temporal.PlainDate

required

The check-out date (ISO string or PlainDate object)

return

number

The number of nights between check-in and check-out

Example:

import { getNumberOfNights } from './utils/utils.js'

const nights = getNumberOfNights('2026-03-10', '2026-03-15')
console.log(nights) // 5

getTotalPrice()

Calculates the total room price for a date range. Signature:

function getTotalPrice(room, checkIn, checkOut): number

room

Room

required

The room object containing pricePerNight

checkIn

string | Temporal.PlainDate

required

The check-in date

checkOut

string | Temporal.PlainDate

required

The check-out date

return

number

The total price (pricePerNight × numberOfNights)

Example:

import { getTotalPrice } from './utils/utils.js'

const total = getTotalPrice(
  room, // { pricePerNight: 100 }
  '2026-03-10',
  '2026-03-15'
)
console.log(total) // 500 (100 × 5 nights)

getExtrasPrice()

Calculates the total price of extras. Signature:

function getExtrasPrice(extras): number

extras

Extra[]

required

Array of extra objects, each containing price and quantity properties

return

number

The sum of all extras (price × quantity for each extra)

Example:

import { getExtrasPrice } from './utils/utils.js'

const extras = [
  { name: 'Breakfast', price: 15, quantity: 2 },
  { name: 'Parking', price: 10, quantity: 5 }
]

const extrasTotal = getExtrasPrice(extras)
console.log(extrasTotal) // 80 (30 + 50)

updateTotalPriceWithExtras()

Calculates the final total price including extras. Signature:

function updateTotalPriceWithExtras(reservation, extras): number

reservation

Reservation

required

The reservation object containing the base totalPrice

extras

Extra[]

required

Array of extra objects to add to the total

return

number

The updated total price (reservation.totalPrice + extras total)

Example:

import { updateTotalPriceWithExtras } from './utils/utils.js'

const extras = [
  { name: 'Breakfast', price: 15, quantity: 2 }
]

const finalPrice = updateTotalPriceWithExtras(
  reservation, // { totalPrice: 500 }
  extras
)
console.log(finalPrice) // 530

History Management

getReservationsPlusHistory()

Combines active reservations and historical reservations. Signature:

function getReservationsPlusHistory(hotel): Reservation[]

hotel

Hotel

required

The hotel object containing reservations and history arrays

return

Reservation[]

A deep clone of all reservations (active + history)

Purpose: Creates a combined array of both active and archived reservations using structuredClone to prevent mutations to the original arrays. Example:

import { getReservationsPlusHistory } from './utils/utils.js'

const allReservations = getReservationsPlusHistory(hotel)
console.log(allReservations.length) // Total count of all reservations

This function uses structuredClone to create a deep copy, ensuring that modifications to the returned array don’t affect the original hotel data.

Getting Started

Core Concepts

API Reference

Guides

Utilities

Reservation Management

createUniqueReservationId()

getReservationById()

archiveReservation()

createInvoice()

getCancellationCharge()

Room Management

getRoomByNumber()

getRoomsByStatus()

getRoomsByType()

isRoomAvailable()

getReservedRoomsByDate()

getReservedRoomByRoomNumber()

Pricing Functions

getNumberOfNights()

getTotalPrice()

getExtrasPrice()

updateTotalPriceWithExtras()

History Management

getReservationsPlusHistory()

Build docs developers (and LLMs) love

Getting Started

Core Concepts

API Reference

Guides

Utilities

​Reservation Management

​createUniqueReservationId()

​getReservationById()

​archiveReservation()

​createInvoice()

​getCancellationCharge()

​Room Management

​getRoomByNumber()

​getRoomsByStatus()

​getRoomsByType()

​isRoomAvailable()

​getReservedRoomsByDate()

​getReservedRoomByRoomNumber()

​Pricing Functions

​getNumberOfNights()

​getTotalPrice()

​getExtrasPrice()

​updateTotalPriceWithExtras()

​History Management

​getReservationsPlusHistory()

Build docs developers (and LLMs) love

Reservation Management

createUniqueReservationId()

getReservationById()

archiveReservation()

createInvoice()

getCancellationCharge()

Room Management

getRoomByNumber()

getRoomsByStatus()

getRoomsByType()

isRoomAvailable()

getReservedRoomsByDate()

getReservedRoomByRoomNumber()

Pricing Functions

getNumberOfNights()

getTotalPrice()

getExtrasPrice()

updateTotalPriceWithExtras()

History Management

getReservationsPlusHistory()