📚 Library Management API

A backend system for managing a digital library, built with Express.js, TypeScript, and MongoDB. It supports book cataloging, borrowing workflows, and strict data validation using Mongoose and Zod.

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Looking for the frontend? 👉 https://github.com/coder7475/libraray_management_frontend

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🚀 Features

• ✅ RESTful API for managing books and borrowing
• 📦 Modular project structure using TypeScript
• 🌿 Environment configuration using .env
• 🔐 Robust validation using Zod + Mongoose
• 📊 MongoDB Aggregation for borrow summary
• 🧠 Static & Instance Methods for business logic
• ⛔ Mongoose Middleware (pre, post) support
• 🔍 Filter & Sort query parameters

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📁 Project Structure

.
├── README.md
├── biome.json               # BiomeJS config for linting & formatting
├── package.json             # Project metadata
├── pnpm-lock.yaml           # Lockfile
├── tsconfig.json            # TS config for dev
├── tsconfig.build.json      # TS config for prod build
└── src
    ├── app.ts               # Express app config
    ├── server.ts            # Entry point
    ├── configs/             # Env & DB setup
    ├── controller/          # Business logic
    ├── interfaces/          # TypeScript interfaces
    ├── middlewares/         # Error handler, Zod validation
    ├── models/              # Mongoose models (Book, Borrow)
    ├── routes/              # Express route definitions
    └── schemas/             # Zod validation schemas

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🎨 API Design

📘 Book Endpoints

Method	Endpoint	Description
POST	/api/books	Add a new book
GET	/api/books	List all books (with filter & sort)
GET	/api/books/:id	Get a single book by ID
PUT	/api/books/:id	Update book fields (e.g., copies)
DELETE	/api/books/:id	Delete a book

📖 Borrow Endpoints

Method	Endpoint	Description
POST	/api/borrow	Borrow a book (checks quantity, updates copies, handles availability flag)
GET	/api/borrow	Aggregated borrow summary by book (title, isbn, totalQuantity)

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🛠️ Getting Started

1️⃣ Clone & Install

git clone https://github.com/coder7475/library_management_apis.git
cd library_management_apis
pnpm install

2️⃣ Environment Setup

Create a .env file in the root directory:

PORT=5000
HOST=localhost
NODE_ENV=development
MONGODB_URI="mongodb://127.0.0.1:27017/your_db_name"

3️⃣ Run in Development

pnpm run dev

4️⃣ Format & Lint

pnpm format && pnpm lint

5️⃣ Build for Production

pnpm run build

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🔎 API Query Parameters

For /api/books:

Query Param	Description
filter	Filter books by genre
sortBy	Field to sort by (e.g., title)
sort	Sort order: asc or desc
limit	Limit number of books returned
page	Current page for pagination

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📈 Data Model

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⚙️ Business Logic

• ✅ Prevent borrow if available copies < requested quantity
• ➖ Deduct quantity from book’s copies
• ❌ If copies becomes 0, set available to false
• 📈 Borrow summary via MongoDB aggregation
• 🧠 Logic implemented using static & instance methods

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📦 Built With

• Express
• TypeScript
• MongoDB + Mongoose
• Zod
• pnpm
• Biome

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📄 License

Licensed under the MIT License. Free to use and modify.