Full Stack Developer Technical Interview Preparation

1. React (Frontend)

• Component Lifecycle: Understand mounting, updating, and unmounting phases.
• State Management: useState, useReducer, Context API, and Redux.
• Hooks: useEffect, useMemo, useCallback, useRef.
• React Router: Route, Link, useParams, useNavigate.
• Optimization: Lazy loading, memoization, avoiding unnecessary re-renders.
• Testing: Jest, React Testing Library, Enzyme.
• Error Handling: Error boundaries, try/catch in async operations.

2. Node.js (Backend)

• Express.js: Middleware, Routing, Error Handling.
• Authentication: JWT, OAuth, Passport.js.
• Asynchronous Programming: Callbacks, Promises, Async/Await.
• Database Connectivity: Using MySQL with Node.js (mysql2, Sequelize, Knex.js).
• RESTful APIs & GraphQL: CRUD operations, API versioning, GraphQL basics.
• Security Best Practices: Helmet.js, CORS, Rate limiting, Input validation.
• Testing: Mocha, Chai, Jest, Supertest.

3. MySQL (Database)

• Schema Design: Normalization, Indexing, Foreign keys.
• Queries: Joins, Subqueries, Transactions.
• Optimization: Query optimization, Indexing strategies, Partitioning.
• ORMs & Query Builders: Sequelize, Knex.js.
• Database Security: User roles, Prepared Statements to prevent SQL Injection.

4. System Design & Architecture

• MVC Pattern: Structure a full stack application using MVC.
• Scalability: Load balancing, Caching (Redis), Microservices vs Monolith.
• Message Queues: RabbitMQ, Kafka.
• Containerization & Deployment: Docker, Kubernetes, CI/CD pipelines.
• Cloud Services: AWS, Firebase, DigitalOcean.

5. Common Interview Questions

• Explain the Virtual DOM and how React updates UI efficiently.
• How does React handle state updates, and when should you use useReducer over useState?
• How does event delegation work in React?
• Explain the difference between useEffect with an empty dependency array and one with dependencies.
• How does Node.js handle multiple concurrent requests?
• Explain how you would structure a scalable REST API in Node.js.
• How do indexes improve MySQL performance?
• How do transactions work in MySQL, and why are they important?
• How would you optimize a slow SQL query?

6. Hands-on Practice

• Build a simple CRUD application using React, Node, and MySQL.
• Implement authentication using JWT in a full stack app.
• Optimize API performance using caching and indexing.
• Deploy an app on AWS or Firebase.