Node.js + MongoDB Assignment API

Simple backend API built with Node.js, Express and MongoDB for an assignment demo. The project includes JWT authentication, class-based error handling, pagination, aggregation with $lookup, search, and a clean folder structure.

Tech Stack

• Node.js
• Express.js
• MongoDB + Mongoose
• JWT

Features

• 4 collections: Users, Posts, Comments, Categories
• Required 10+ APIs
• Pagination in all list APIs
• Aggregation with $lookup
• Search posts by title or content
• Class-based custom error handling
• JWT auth for protected routes
• Bonus: top 3 users with most posts
• Bonus: latest posts first sorting
• Bonus: $group and $facet aggregation usage

Folder Structure

src/
  config/
  controllers/
  middlewares/
  models/
  routes/
  utils/
  app.js
  server.js

How to Run

1. Install dependencies:

npm install

2. Create .env from .env.example

PORT=5000
MONGODB_URI=mongodb://127.0.0.1:27017/assignment_db
JWT_SECRET=your_super_secret_key
JWT_EXPIRES_IN=7d
NODE_ENV=development

3. Start the server:

npm run dev

Scripts

• npm run dev - start server with watch mode
• npm start - start server normally

Main APIs

Auth

• POST /api/auth/register - Register user and get token
• POST /api/auth/login - Login and get token
• GET /api/auth/me - Get logged in user profile

Users

• POST /api/users - Create User
• GET /api/users?page=1&limit=10 - Get All Users
• GET /api/users/:id - Get Single User
• DELETE /api/users/:id - Delete User
• GET /api/users/top-posters - Top 3 users with most posts

Categories

• POST /api/categories - Create Category
• GET /api/categories?page=1&limit=10 - Get All Categories

Posts

• POST /api/posts - Create Post
• GET /api/posts?page=1&limit=10 - Get All Posts
• GET /api/posts/:id - Get Post by ID with user, category and comments
• PATCH /api/posts/:id - Update Post
• GET /api/posts/search?query=node&page=1&limit=10 - Search posts

Comments

• POST /api/comments - Add Comment
• GET /api/comments/post/:postId?page=1&limit=10 - Get Comments by Post

Protected Routes

Use JWT token in header:

Authorization: Bearer your_token_here

Protected routes:

• GET /api/auth/me
• POST /api/categories
• POST /api/posts
• PATCH /api/posts/:id
• POST /api/comments

Example Request Body

Create User

{
  "name": "Arpit",
  "email": "arpit@example.com",
  "password": "123456"
}

Create Category

{
  "name": "Technology",
  "description": "Tech related posts"
}

Create Post

{
  "title": "Node Assignment",
  "content": "This is a sample post content",
  "category": "category_object_id_here"
}

Add Comment

{
  "content": "Nice post",
  "postId": "post_object_id_here"
}

Assignment Mapping

• User APIs: done
• Post APIs: done
• Comment APIs: done
• Search API: done
• Pagination: done
• Error handling: done
• JWT: added
• Bonus features: done