🎯 Goal:

Crack the Sr. Frontend Developer Interview (3–5 yrs exp) by mastering React.js ecosystem, performance optimization, TypeScript, APIs, CI/CD, and frontend architecture.

🧩 1. Core Frontend Fundamentals
📘 HTML5

Semantic HTML (header, section, article, etc.)

Accessibility (ARIA roles, alt attributes, tab index)

SEO best practices

📘 CSS3

Flexbox & Grid layouts

Responsive design (media queries, mobile-first)

Animations & transitions

Pseudo-classes & selectors

Preprocessors: Sass / Tailwind CSS

🧠 Practice: Rebuild a responsive portfolio or landing page from Figma.

⚙️ 2. JavaScript (ES6+)

let, const, arrow functions, destructuring

Template literals, spread/rest operators

Async/await, Promises

Array & object methods (map, filter, reduce)

Closures, hoisting, scope

Event loop, call stack, microtasks

🧠 Project Practice: Build a small “To-Do App” using vanilla JS (with localStorage).

⚛️ 3. React.js + Next.js (Main Focus)
React.js:

Functional Components, JSX, and Hooks (useState, useEffect, useRef, useMemo, useCallback)

Component architecture & props drilling

State management:

Redux Toolkit

Context API + custom hooks

Zustand (optional advanced)

Lifecycle in hooks

React Router (v6)

Performance:

Code splitting (React.lazy, Suspense)

Memoization

React DevTools profiling

Next.js:

File-based routing

getStaticProps, getServerSideProps

API Routes

Image optimization & Head component

Server Components (Next 13+)

Deployment (Vercel)

🧠 Project: Create a “Blog or Dashboard” using Next.js + REST API + Tailwind CSS.

🌐 4. API Integration & Backend Collaboration

RESTful APIs (GET, POST, PUT, DELETE)

Axios / Fetch usage

Error handling & interceptors

JSON parsing and schema validation

GraphQL (optional bonus)

Postman usage

🧠 Practice: Integrate a public API (like OpenWeather or GitHub users) into a React app.

🧰 5. TypeScript for React

Basic types, interfaces, enums

Generics

Type assertions

Typing components, props, hooks

Avoiding any

🧠 Exercise: Convert one existing React project to TypeScript.

🔁 6. CI/CD + DevOps Basics

Understand CI/CD pipelines (GitHub Actions, Jenkins)

Automated builds & deployments (Vercel, Netlify)

Linting (ESLint), formatting (Prettier)

Unit testing: Jest + React Testing Library

☁️ 7. Cloud & Deployment

Hosting on AWS / Azure / Heroku / Vercel

Environment variables & secrets

Build optimization

🐳 8. Docker & Kubernetes (Basic Understanding)

Why containerization matters

Dockerfile basics

docker-compose

Deploying a React app in a container

🌍 9. Performance, Scalability & Accessibility

Lighthouse metrics (LCP, FID, CLS)

Lazy loading images/components

Code splitting and dynamic imports

ARIA roles & keyboard navigation

SEO with Next.js

🧪 10. Git, GitHub, and Collaboration

Branching strategy (feature, develop, main)

Pull Requests & Code Reviews

Merge conflicts & rebasing

GitHub Actions basics

🎓 11. Interview Preparation (Practical Round Focus)
Technical Questions

Explain how React reconciles the virtual DOM.

Difference between SSR, SSG, and CSR in Next.js.

How do you optimize React app performance?

Difference between Redux and Context API?

How to handle authentication in React?

What are REST and GraphQL? Which do you prefer?

How would you dockerize a React app?

Coding Challenges

Reverse a string / array manipulation

Debounce & Throttle function

Fetch API + display list

Build a pagination component

System Design (Frontend-Level)

How would you structure a large React app?

Folder architecture best practices

Component communication patterns

🧭 12. 7-Day Study Plan (Quick Revision)
Day	Topics
1	HTML5, CSS3, Responsive UI
2	JavaScript ES6+ Deep Dive
3	React.js Core + Hooks
4	Redux, Context, API integration
5	Next.js, Routing, SSR/SSG
6	TypeScript, CI/CD, Docker basics
7	Mock Interview + Projects Review