Bookstore RESTful API

🎯 Objective

This project implements a RESTful API for a bookstore inventory system using Node.js, the Express framework, and TypeScript. The API supports standard CRUD (Create, Read, Update, Delete) operations for managing books and includes advanced filtering capabilities and a complex logical operation for calculating genre-specific discounts.

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🏗️ Architecture

The API is built using an n-layered architecture to ensure separation of concerns and maintainability:

• Controller Layer: Handles incoming HTTP requests, performs input validation, and sends responses.
• Service Layer: Contains the business logic, including the core logic for the discount calculation.
• Repository Layer: Manages data access, currently utilizing an in-memory array as a mock database.

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🚀 Getting Started

Prerequisites

• Node.js (v16 or higher recommended)
• npm

Installation and Setup

1. Clone the repository:

   git clone https://github.com/Delport121/Bookstore_API.git
   cd Bookstore_API

2. Install dependencies:

   npm install

   This installs Express, TypeScript, and necessary development tools like ts-node, nodemon, and jest.

3. Create Environment File (.env) (Optional): Create a file named .env in the root directory for custom configuration. Use .env.example as a template:

   cp .env.example .env

   Or on Windows PowerShell:

   Copy-Item .env.example .env

   Example .env contents:

   PORT=3000
   NODE_ENV=development
   

4. Run the API in Development Mode:

   npm run dev

   The server will start at http://localhost:3000 (or your configured port) and will automatically restart on code changes.

5. Run the API in Production Mode:

   npm start

Running Tests

Unit tests are included to ensure the correctness of all CRUD operations and the discount calculation logic.

To run the tests:

npm test

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📚 API Endpoints

Book Management (CRUD)

Method	Endpoint	Description	Request Body	Success Response
POST	/books	Adds a new book to the inventory	{"title": "...", "author": "...", "genre": "...", "price": 99.99}	201 Created
GET	/books	Retrieves a list of all books (supports filtering)	None	200 OK (Array of Book objects)
GET	/books/:id	Retrieves details of a book by its ID	None	200 OK (Single Book object)
PUT	/books/:id	Updates details of an existing book	{"price": 89.99, "genre": "..."}	200 OK (Updated Book object)
DELETE	/books/:id	Deletes a book from the inventory	None	204 No Content

Book Filtering (GET /books)

The GET /books endpoint supports the following query parameters for filtering:

Parameter	Type	Description	Example
genre	string	Filter by exact genre (case-insensitive)	?genre=Fiction
author	string	Filter by author name (partial match)	?author=Harper Lee
title	string	Filter by book title (partial match)	?title=Mockingbird
minPrice	number	Filter books with price >= minPrice	?minPrice=50
maxPrice	number	Filter books with price <= maxPrice	?maxPrice=100

Examples:

GET /books?genre=Fiction
GET /books?author=Harper&maxPrice=60
GET /books?minPrice=40&maxPrice=80

Complex Logical Operation (Discount Calculation)

Method	Endpoint	Description	Example Request	Example Response
GET	/books/discounted-price	Calculates the total discounted price for all books in a specific genre based on a given discount percentage	/books/discounted-price?genre=Fiction&discount=10	{"genre": "Fiction", "discount_percentage": 10, "total_discounted_price": 112.50}

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📝 Example Requests

Create a Book

POST http://localhost:3000/books
Content-Type: application/json

{
  "title": "The Great Gatsby",
  "author": "F. Scott Fitzgerald",
  "genre": "Fiction",
  "price": 60.00
}

Get All Books

GET http://localhost:3000/books

Get Books by Genre

GET http://localhost:3000/books?genre=Fiction

Get Book by ID

GET http://localhost:3000/books/1

Update a Book

PUT http://localhost:3000/books/1
Content-Type: application/json

{
  "price": 55.00
}

Delete a Book

DELETE http://localhost:3000/books/1

Calculate Discounted Price

GET http://localhost:3000/books/discounted-price?genre=Fiction&discount=10

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🧪 Testing

The project includes comprehensive unit tests for:

• All CRUD operations (Create, Read, Update, Delete)
• Filtering functionality
• Discount calculation logic
• Edge cases and error handling

Tests are written using Jest and cover both the service layer logic and repository interactions.

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🛠️ Technologies Used

• Node.js - JavaScript runtime
• Express - Web framework
• TypeScript - Type-safe JavaScript
• Jest - Testing framework
• ts-node - TypeScript execution
• nodemon - Development auto-reload

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📂 Project Structure

bookstore-api/
├── src/
│   ├── controllers/     # Request handlers
│   ├── services/        # Business logic
│   ├── repositories/    # Data access
│   ├── models/          # Data types
│   ├── routes/          # API routes
│   └── server.ts        # Application entry point
├── jest.config.js       # Test configuration
├── tsconfig.json        # TypeScript configuration
├── package.json         # Dependencies and scripts
└── README.md           # This file

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