Mini Trello Clone – Backend (Node.js + Express + MongoDB)

A production-ready backend for a Trello-style task management application featuring collaborative boards, lists, cards, and a custom Smart Recommendations Engine.

This system is built using Node.js, Express.js, and MongoDB with JWT authentication. It supports detailed access control, member invitations, drag-and-drop logic (positional indexing), and an NLP-like rule-based recommendation system for due dates and list movements.

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🚀 Features

1. Authentication (JWT)

• User Registration & Login.
• Password hashing using bcrypt.
• Token-based authentication (JWT).
• Secure protected routes.

2. Boards

• Create, update, and delete boards.
• Access Control: Owner vs. Member permissions.
• Invite members via email.
• Fetch all boards a user has access to.

3. Lists

• Create, update, and delete lists within a board.
• Positional Indexing: Handles ordered lists.
• Auto-incrementing list positions.

4. Cards

• Create, update, delete cards.
• Move Logic: Move cards across lists with automatic position shifting.
• Metadata: Priority, labels, assignees, and due dates.
• Strong validation and permission checks.

5. 🧠 Smart Recommendations Engine

A rule-based NLP module that provides:

• Due Date Suggestions: Based on weighted keyword scoring (e.g., "urgent", "asap").
• List Movement Suggestions: Based on status keywords (e.g., "done", "review").
• Related Cards: Grouped by textual similarity using cosine-like scoring.
• Confidence Scoring: Returns a confidence level for every suggestion.

6. Access Control

• Owner: Full update/delete permissions.
• Member: Read, add, and edit cards/lists.
• Middleware ensures no unauthorized access.

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🛠 Tech Stack

• Runtime: Node.js
• Framework: Express.js
• Database: MongoDB + Mongoose
• Auth: JWT (JSON Web Token) & bcrypt.js
• Logic: Custom NLP-like keyword engine
• Architecture: Modular (Controllers, Routes, Services)

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📂 Project Structure

src/
│── controllers/        # Request handlers
│   ├── auth.controller.js
│   ├── board.controller.js
│   ├── list.controller.js
│   ├── card.controller.js
│   └── recs.controller.js
│
│── middlewares/        # Auth & Permission checks
│   ├── auth.middleware.js
│   └── checkBoardAccess.js
│
│── models/             # Mongoose Schemas
│   ├── user.model.js
│   ├── board.model.js
│   ├── list.model.js
│   └── card.model.js
│
│── routes/             # API Route definitions
│   ├── auth.routes.js
│   ├── board.routes.js
│   ├── list.routes.js
│   ├── card.routes.js
│   └── recs.routes.js
│
│── utils/              # Helper functions
│   ├── generateJWT.js
│   ├── textUtils.js
│   └── recommendationsLogic.js
│
├── server.js           # Entry point
└── README.md

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⚙️ Installation & Setup

1. Clone the repository

git clone <repo-url>
cd backend

2. Install dependencies

npm install

3. Configure Environment Variables

Create a .env file in the root directory and add the following:

PORT=8080
MONGO_URI=mongodb://localhost:27017/trello-clone
JWT_SECRET=your_jwt_secret
EXPIRES_IN=7d

4. Run the Server

Development Mode:

npm run dev

Production Mode:

npm start

Server runs on: http://localhost:8080

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📡 API Overview

All protected routes require the following header: Authorization: Bearer <token>

🔐 Authentication

Method	Endpoint	Description
POST	/auth/register	Register a new user
POST	/auth/login	Login and receive JWT

📋 Boards

Method	Endpoint	Description
POST	/boards	Create a board
GET	/boards	Get all boards (Owner/Member)
GET	/boards/:id	Get specific board details
PUT	/boards/:id	Update board (Owner only)
DELETE	/boards/:id	Delete board (Owner only)
POST	/boards/:id/members	Invite user by email

📑 Lists

Method	Endpoint	Description
POST	/boards/:id/lists	Create a new list
GET	/boards/:id/lists	Get ordered lists
PUT	/boards/:id/lists/:listId	Update list
DELETE	/boards/:id/lists/:listId	Delete list

📝 Cards

Method	Endpoint	Description
POST	/card/:boardId/:listId/cards	Create a card
GET	/card/:boardId/cards	Get all cards
PUT	/card/:boardId/cards/:cardId	Update card details
POST	/card/:boardId/cards/:cardId/move	Move card (List/Position)
DELETE	/card/:boardId/cards/:cardId	Delete card

🧠 Smart Recommendations

Method	Endpoint	Description
GET	/boards/:boardId/recommendations	Get AI suggestions

Response Example for Recommendations:

{
  "dueDateSuggestions": [
    {
      "cardTitle": "Fix login bug",
      "suggestedDue": "2025-02-24T09:00:00.123Z",
      "score": 7,
      "confidence": 0.85,
      "reason": "Weighted keywords sum = 7"
    }
  ],
  "moveSuggestions": [
    {
      "cardTitle": "Fix login bug",
      "suggestedListName": "In Progress",
      "confidence": 0.8,
      "reason": "Matched 2 keyword(s)"
    }
  ]
}

---

💡 Recommendation Engine Logic

1. Due Date Logic

Calculates a score based on keywords in the card description:

• +5: urgent, asap
• +3: bug, fix
• +2: review
• +1: meeting, planning

Result:

• Score ≥ 8 → Due in 1 day
• Score ≥ 5 → Due in 2 days
• Score ≥ 3 → Due in 5 days
• Score > 0 → Due in 7 days

2. Move Suggestion Logic

Suggests moving a card to a specific list based on keywords:

• start, doing → "In Progress"
• done, completed → "Done"
• blocked, hold → "Blocked"
• review, pr → "Review"

3. Related Groups Logic

• Tokenizes card titles and descriptions.
• Generates term frequency vectors.
• Computes cosine-like similarity.
• Groups cards with a similarity threshold ≥ 0.25.

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🛡 Security & Standards

• Sanitized Queries: Prevents NoSQL injection.
• Password Encryption: Uses bcrypt (no plaintext storage).
• Role-Based Access: Strict Owner vs. Member separation.
• Environment Config: Sensitive keys stored in .env.

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🔮 Future Enhancements

• Real-time updates using Socket.io.
• Activity Logs / Audit Trails.
• Granular Roles (Admin, Editor, Viewer).
• File Attachments (AWS S3 / Cloudinary).
• Commenting system on cards.

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👤 Author

Samarth Gupta Backend built for the Mini Trello Clone assignment.