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JS Mini Hotel implements several business rules that govern pricing, services, restrictions, and state transitions throughout the reservation lifecycle.

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Room Pricing

Room prices are fixed based on room type and charged per night.

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Price Structure

Room TypePrice per Night
Single€50
Double€80
Suite€150
These prices are defined in the room objects and stored in ~/workspace/source/data/rooms.json. The base price is multiplied by the number of nights to calculate the room portion of the total cost.

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Price Calculation

The total reservation price is calculated as: 
totalPrice = (pricePerNight × nights) + sum(extras)
Where:
  • pricePerNight is the room’s base rate
  • nights is the number of nights (checkOut - checkIn)
  • sum(extras) is the total of all extra services (price × quantity for each extra)

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Extra Services

Guests can add optional services to their reservations. Services are categorized as daily charges or one-time fees.

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Available Services

These services are charged per day/night of the stay:
ServicePrice per DayExample Usage
Breakfast€10Charged for each night of stay
Parking€15Charged for each night of stay
These services are charged as a single fee:
ServicePriceDescription
Late Check-out€30One-time fee for extended checkout
Early Check-in€20One-time fee for early arrival

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Extra Service Structure

Each extra service in the reservation has this structure: 
{
  "name": "Breakfast",
  "price": 10,
  "quantity": 5
}
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name
string
Name of the service (e.g., “Breakfast”, “Parking”, “Late Checkout”)
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price
number
Price per unit in euros
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quantity
number
Number of units (typically equals number of nights for daily services, 1 for one-time services)
Extras can be added to reservations using the addExtras() function, which automatically recalculates the total price.

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Night Restrictions

Reservations must comply with minimum and maximum night limits.
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minimum
number
default:"1"
Minimum stay: 1 nightThe check-out date must be at least one day after the check-in date.
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maximum
number
default:"14"
Maximum stay: 14 nightsReservations cannot exceed 14 consecutive nights.

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Implementation

This validation is enforced in ~/workspace/source/utils/validation.js:92-95: 
if (getNumberOfNights(checkIn, checkOut) > 14) {
  validation.status = false
  validation.message = 'Solo se puede reservar hasta 14 noches.'
}
The minimum of 1 night is implicitly enforced by the date range validation that requires check-out to be after check-in.

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Room Status Transitions

Rooms transition through different states based on reservations and hotel operations.

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Status Types

Defined in ~/workspace/source/utils/constants.js:9-13: 
export const ROOM_STATUS = {
  AVAILABLE: 'available',
  OCCUPIED: 'occupied',
  MAINTENANCE: 'maintenance',
}

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Status Flow

Status: "available"The room is ready for new reservations and can be booked by guests.Transitions to:
  • occupied when a guest checks in
  • maintenance when maintenance is required
Status: "occupied"The room is currently occupied by a guest with an active reservation.Transitions to:
  • available when the guest checks out
  • maintenance if issues are reported during stay
Trigger: Set during the checkIn() function
Status: "maintenance"The room is unavailable due to maintenance, cleaning, or repairs.Transitions to:
  • available when maintenance is complete
Rooms in maintenance status cannot be booked and are excluded from availability searches.

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Reservation Status Flow

Reservations progress through a lifecycle from creation to completion or cancellation.

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Status Types

Defined in ~/workspace/source/utils/constants.js:1-7: 
export const RESERVATION_STATUS = {
  CONFIRMED: 'confirmed',
  CHECKED_IN: 'checked-in',
  CHECKED_OUT: 'checked-out',
  OCCUPIED: 'occupied',
  CANCELLED: 'cancelled',
}

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Status Flow

Status: "confirmed"Initial status when a reservation is created. The room is reserved for the specified dates.Location: Active reservations array (hotel.reservations)Allowed actions:
  • Add extras
  • Check-in (on or after check-in date)
  • Cancel reservation
Transitions to:
  • checked-in via checkIn() function
  • cancelled via cancelReservation() function
Status: "checked-in"Guest has arrived and checked into the room. The room status is set to occupied.Location: Active reservations array (hotel.reservations)Validation:
  • Can only check in from confirmed status
  • Check-in date must be today or in the past
  • Reservation must exist
Transitions to:
  • checked-out via checkOut() function
  • cancelled via cancelReservation() (with potential penalties)
Status: "checked-out"Guest has completed their stay and checked out. Invoice is generated.Location: History array (hotel.history)Effects:
  • Room status changed to available
  • Reservation moved from hotel.reservations to hotel.history
  • Invoice generated with full breakdown
Final state: No further transitions
Status: "cancelled"Reservation was cancelled before or during the stay.Location: History array (hotel.history)Cancellation policy:
  • More than 7 days before check-in: No charge
  • 3-7 days before check-in: 50% of total
  • Less than 3 days before check-in: 100% of total
Effects:
  • Room is freed and becomes available
  • Reservation moved to history
  • Penalty calculated based on cancellation policy
Final state: No further transitions
Reservations can only transition through valid state changes. For example, you cannot check out a reservation that is still in confirmed status - it must be checked-in first.

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State Validation

The system enforces state transition rules:
  • Check-in requires status confirmed
  • Check-out requires status checked-in
  • Cancellation allowed from confirmed or checked-in
  • Adding extras allowed for confirmed and checked-in statuses
Once a reservation reaches checked-out or cancelled status, it is moved to the history array and becomes immutable.

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