Node.js MongoDB API

A simple Node.js Express API that connects to MongoDB and retrieves user data with age filtering.

Approach

This solution implements a RESTful API endpoint that retrieves user data from MongoDB. The implementation includes proper error handling for invalid ObjectIds and enforces an age restriction (>21) on the queries. The code follows best practices with async/await pattern and proper separation of concerns.

API Documentation

The API is documented using Swagger UI. After starting the server, you can access the interactive API documentation at:

http://localhost:3000/swagger-ui

This provides a detailed overview of all available endpoints, request/response schemas, and allows you to test the API directly from the browser.

Prerequisites

Installing Node.js

Installing on macOS

1. Using Homebrew:

# Install Homebrew if you haven't already
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

# Install Node.js
brew install node

# Verify installation
node --version
npm --version

1. Alternatively, download the installer from Node.js official website

Installing on Linux (Ubuntu/Debian)

1. Using apt:

# Add NodeSource repository
curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash -

# Install Node.js
sudo apt install -y nodejs

# Verify installation
node --version
npm --version

Installing on Windows

1. Download the Windows Installer from Node.js official website
2. Run the installer (e.g., node-v20.x.x-x64.msi)
3. Follow the installation wizard
4. Open Command Prompt or PowerShell and verify installation:

node --version
npm --version

Installing MongoDB

Installing MongoDB on macOS

1. Using Homebrew:

# Install Homebrew if you haven't already
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

# Install MongoDB
brew tap mongodb/brew
brew install mongodb-community

# Start MongoDB service
brew services start mongodb-community

Installing MongoDB on Linux (Ubuntu/Debian)

# Import MongoDB public key
curl -fsSL https://www.mongodb.org/static/pgp/server-7.0.asc | sudo gpg -o /usr/share/keyrings/mongodb-server-7.0.gpg --dearmor

# Add MongoDB repository
echo "deb [ arch=amd64,arm64 signed-by=/usr/share/keyrings/mongodb-server-7.0.gpg ] https://repo.mongodb.org/apt/ubuntu $(lsb_release -cs)/mongodb-org/7.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-7.0.list

# Update package list and install MongoDB
sudo apt update
sudo apt install -y mongodb-org

# Start MongoDB service
sudo systemctl start mongod
sudo systemctl enable mongod

Installing MongoDB on Windows

1. Download the MongoDB Community Server installer from the official MongoDB website
2. Run the installer and follow the installation wizard
3. Choose "Complete" setup type
4. Install MongoDB Compass (optional but recommended GUI tool)
5. MongoDB will be installed as a Windows Service and start automatically

Verifying MongoDB Installation

To verify that MongoDB is running correctly:

# Connect to MongoDB shell
mongosh

# You should see a welcome message and a prompt
# Type the following to check the version
db.version()

Setup

Install dependencies

npm install

Configure environment variables

cp .env.example .env

Edit the .env file with your specific configuration:

# Server Configuration
PORT=3000

# MongoDB Configuration
MONGODB_URI=mongodb://localhost:27017/userdb

# API Configuration
NODE_ENV=development

Start the development server

npm run dev:ts

Build and start the production server

npm run build
npm start

Environment Variables

• PORT: The port number for the server (default: 3000)
• MONGODB_URI: MongoDB connection string (default: mongodb://localhost:27017/userdb)
• NODE_ENV: Application environment (development/production)

API Endpoints

Create User

POST /users

• Body:

{
  "name": "John Doe",
  "email": "[email protected]",
  "age": 25
}

• Response: 201 Created
• Note: Age must be greater than 21

Get User

GET /users/:id

• Response: 200 OK
• Note: Only returns users with age > 21

Update User

PUT /users/:id

• Body:

{
  "name": "John Doe Updated",
  "email": "[email protected]",
  "age": 26
}

• Response: 200 OK
• Note: All fields are optional, but age must be > 21 if provided

Delete User

DELETE /users/:id

• Response: 204 No Content

Error Responses

• 400 Bad Request: Invalid input or age requirement not met
• 404 Not Found: User doesn't exist
• 500 Internal Server Error: Server-side error