Parking Fee Calculator

You are tasked to build a Parking Fee Calculator, that will help to calculate parking fees and thus help users decide where to park. These are the carparks that will be considered in this application:

For each of the car park, it has different parking rules, the rules for weekday and weekend are also different, in general there are three kinds of parking rule,

Fixed per entry: Per Entry charge - $4.36

Fixed first X minutes, then subsequent Y mins charge: First hour(X=60) at $1.95 Every subsequent 15 minutes(Y=15) at $0.55

Fixed per X minutes: $0.55 every 15 minutes(X=15)

Project Structure

my-nodejs-app
|-- api-tests
├── src
│   ├── app.ts
│   ├── controllers
│   │   └── FeeCalculationController.ts
│   ├── routes
│   │   └── index.ts
│   ├── services
│   │   └── FeeCalculationService.ts
|   │   └── fee
|   │       └── BaseFee.ts
|   │       └── FeeCalculator.ts
|   │       └── FixedFeePerEntry.ts
|   │       └── FixedFeePerXMinutes.ts
|   │       └── FixedFirstXMinutes.ts
│   └── types
│       └── index.ts
├── package.json
├── tsconfig.json
└── README.md

File Descriptions

• src/app.ts: This file is the entry point of the application. It creates an instance of the express app, sets up middleware and routes, and starts the server.
• src/controllers/FeeCalculationController.ts: This file exports a class FeeCalculationController which has a method getParkingFee that handles the /calculateFee route of the application and returns the fee.
• src/routes/index.ts: This file exports a function setRoutes which sets up the routes for the application. It uses the FeeCalculationController to handle the /calculateFee route.
• src/types/index.ts: This file exports the types and interfaces used in the calculation, such as CarPark and CarFee.
• src/services/fee/BaseFee.ts: This file implements the Fee interface and implements the isFit method, which returns the time period that falls within the ruleset, or a false result if the inputted time period does not fall within the ruleset at all.
• src/services/fee/FeeCalculator.ts: This file implements the calculateParkingFee method and its helper methods.
• src/services/fee/FixedFeePerEntry.ts: This file defines the ruleset for which there is a fixed fee per entry for the time period defined in the ruleset.
• src/services/fee/FixedFeePerXMinutes.ts: This file defines the ruleset for which there is a fixed fee per X minutes for the time period defined in the ruleset. Each block will be rounded up (i.e. if X=15, if the parking duration is 50minutes, it will be counted as 4 blocks of X)
• src/services/fee/FixedFirstXMinutes.ts: This file defines the ruleset for which there is a fixed fee for the first X minutes, and thereafter the remaining time is charged for another fixed fee per Y minutes. Similarly, each block will be rounded up. (i.e. if X=60 and Y=15, if the parking duration is 110minutes the parking charge will be xFee + 4 * yFee).
• tsconfig.json: This file is the configuration file for TypeScript. It specifies the compiler options and the files to include in the compilation.
• package.json: This file is the configuration file for npm. It lists the dependencies and scripts for the project.
• README.md: This file contains the documentation for the project.

Class Diagram

Time Sequence Diagram

install

npm install

run local

npm run dev

it will run at localhost:3000, and has a endpoint /calculateFee

run test

npm t

run api-test

npm run apitest

How to use it

You need to finish 3 tasks. if all 3 tasks finished, when you run the test in feeCalculationService.test.ts, the test will pass!

Task 1

---

can checkout the branch step1 to start

git checkout step1

Requirement

You need to implement the calculateCost method in FixedFirstXMinutes, it based on the rule first X mintues charge a fixed amount, for the subsequence, each Y mintues will charge a fee, for example:

10:00 - 16:00:

First 2 hour at $5

Every subsequent 15 minutes at $0.55

X=120, Y=15

test case:

entryTime: 10:00, exitTime: 13:07

10:00-12:00: $5

12:01-13:07 (1*4+1)*0.55=$2.75

in total: 5+2.75=$7.75

Definiation of Done

all test cases in FixedFirstXMinutes.test.ts are passed

Task 2

---

you can continue your implementation without the checkout command if you finished step1, or start directly by checkout the branch step2

git checkout step2

Requirement

You need to implement the isFit method inside the BaseFee class, it's to comparing the input startTime and endTime, whether it fit the current rule, if yes, need to return the actual start time and actual end time,

for example: rule configed: 10:00-13:00

case 1: input param: startTime: 9:00, endTime: 9:59 output: { isFit: false }

case 2: input param: startTime: 9:00, endTime: 11:01 output: { isFit: true, startTime: 10:00, endTime: 11:01 }

Definition of Done

All the test cases in BaseFee.test.ts are passed

Task 3

---

you can continue your implementation without the checkout command if you finished step2, or start directly by checkout the branch step3

git checkout step3

Requirement

You need to finish the final logic, the calculateParkingFee method in FeeCalculator.ts to calculate the parking fee,

1. need to check whether it's within grace peroid, if yes return 0
2. need to check whether it's weekend, if yes need to use the weekend day rule instead of the week day, the checkIsWeekend method will return true if it's weekend
3. split the start time and end time into days with calculateDays method
4. iterate the rules with each days and sum the result

Test cases:

entryTime = "2021-01-01T10:00";

exitTime = "2021-01-02T11:00";

parking in plazaSingapura

day 1:

10:00-11:00: 1.95

11:01-17:59: 7*4*0.55 = 15.40

18:00-23:59: 3.25

day 2:

00:00-02:59: 3*4*0.55 = 6.60

3:00-5:00: 3.25

5:01-11:00: 6*4*0.55 = 13.2

total: 1.95 + 15.40 + 3.25 + 6.60 + 3.25 + 13.2 = 43.65

Definition of Done

All the test cases in FeeCalculator.test.ts are passed and the test cases in feeCalculationService.test.ts are all passed