🧪 The Complete Frontend Interview Preparation Kit

390+ coding problems + 568+ real interview questions covering JavaScript, React, CSS, TypeScript, System Design, Performance, and more — everything you need to crack frontend interviews at top companies.

• What Is This?
• Repository Structure
• 📋 Real Interview Questions
• 📝 150 Coding Practice Questions
• 🧩 JavaScript Logic Problems
• 📊 Real-World Dataset Challenges
• How to Use
• Study Strategy
• Sources & Credits
• Connect With Me

This is a hands-on, practice-first frontend interview preparation repository. Instead of just reading theory, you solve real problems, practice real interview questions, and work with real-world datasets — exactly how companies test you.

Built for:

• Frontend developers preparing for interviews at Flipkart, Razorpay, Swiggy, Google, Meta, Atlassian, Microsoft, CRED, Meesho, Walmart, Rippling and more
• Anyone who wants to go beyond LeetCode and practice actual interview patterns
• Self-learners who want structured, progressive practice material

frontend-interview-mastery/
│
├── real-interview-questions/         # 🔥 500+ real interview questions (13 files)
│   ├── react.md
│   ├── javascript.md
│   ├── html.md
│   ├── css.md
│   ├── typescript.md
│   ├── performance.md
│   ├── accessibility.md
│   ├── system-design.md
│   ├── build-tools-devops.md
│   ├── auth-security.md
│   ├── debugging-devtools.md
│   ├── other.md
│   └── behavioral.md
│
├── 150-questions/                    # 📝 150 coding practice questions
│   ├── CODING-PRACTICE-150-QUESTIONS.md
│   └── polyfills/
│       ├── map.js
│       ├── filter.js
│       ├── reduce.js
│       └── includes.js
│
├── javascript-logic-problems/        # 🧩 45 JS logic problems with solutions
│   ├── JAVASCRIPT-LOGIC-PROBLEMS.md
│   ├── n-01-check-prime-number.js
│   ├── s-01-reverse-a-string.js
│   └── ... (45 solution files)
│
├── data-set-questions/               # 📊 5 real-world dataset challenges
│   ├── customer/                     #     40 questions on customer orders
│   ├── employee/                     #     50 questions on employee data
│   ├── hospital/                     #     50 questions on patient records
│   ├── job-board/                    #     50 questions on job/applicant data
│   └── students/                     #     50 questions on student records
│
├── Questions.txt                     # Raw interview questions source file
└── README.md                         # ← You are here

568+ unique questions picked from real LinkedIn posts where developers shared their interview experiences at IBM, EY, Deloitte, Intuit, Amazon, Coursera, Cognizant, Nagarro, MakeMyTrip, Zomato, Zepto, fintech companies, and more. Each question is unique — when the same question has been asked in multiple ways, alternate phrasings are shown as sub-bullets.

1. Pick a category from the table above
2. Read each question — can you answer it confidently?
3. Check alternate phrasings — interviewers ask the same thing differently
4. Practice explaining out loud — if you can't explain clearly, revisit the concept
5. Track your progress — mark questions you're confident on vs need to review

📂 Location: 150-questions/

A master list of 150 questions organized into 7 sections with a priority system based on real interview frequency:

Includes: 🔴🟡🟢 Priority labels · Company-specific focus areas · 3-week study schedule · Polyfill implementations in polyfills/

👉 Open the full question bank →

📂 Location: javascript-logic-problems/

45 solved problems with clean, well-commented JavaScript solutions covering:

Each file is self-contained with the problem, approach, and solution.

👉 Open the problem bank →

📂 Location: data-set-questions/

Each module contains a rich, realistic dataset (data.js), a detailed question bank (QUESTION.MD), and clean solution code (answer.js).

git clone https://github.com/goswamikaushik/frontend-interview-mastery.git
cd frontend-interview-mastery

Browser Console:

// Copy-paste the contents of data.js into your browser console
// Then start solving questions

Node.js:

cd data-set-questions/customer
node data.js
node answer.js

Your IDE:

const data = require("./data");
// Start solving!

Each QUESTION.MD file includes ✅ Expected output · 💡 Hints · 📝 Constraints

WEEK 1 — Foundation (Polyfills + Output Questions)
  Day 1–2:  Array polyfills (map, filter, reduce, forEach, find)
  Day 3–4:  Function utilities (debounce, throttle, curry, bind)
  Day 5–6:  Output-based questions (closures, hoisting, event loop)
  Day 7:    Promise polyfills (Promise.all, retry, sleep)

WEEK 2 — Core Skills (Data Manipulation + React)
  Day 8–9:  Object utilities (deepClone, flattenObject, groupBy)
  Day 10–11: Pick any dataset module → solve Easy + Medium
  Day 12–13: React coding problems (custom hooks, bug fixes)
  Day 14:   Real interview questions → JS + React files

WEEK 3 — Hard + Machine Coding + Interview Prep
  Day 15–16: UI machine coding (star rating, accordion, tabs)
  Day 17–18: System Design questions + Performance questions
  Day 19–20: Pick another dataset module → solve Hard questions
  Day 21:    Behavioral questions + revisit weak spots

• ✅ All P1 questions from 150-questions/ (57 questions)
• ✅ All output-based questions (Q71–Q94)
• ✅ At least 8 React questions solved
• ✅ At least 2 UI components built from scratch
• ✅ Complete Easy + Medium from at least 2 dataset modules
• ✅ Can answer 70%+ of real-interview-questions/javascript.md confidently

Transparency Note: This repository is built using a combination of sources to ensure comprehensive, real-world interview coverage.

Found a bug in an expected output? Have a better solution approach? Want to add more questions?

1. Fork this repository
2. Create your branch (git checkout -b feature/better-solution)
3. Commit your changes (git commit -m 'Add optimized Q15 solution')
4. Push to the branch (git push origin feature/better-solution)
5. Open a Pull Request

If this helped your interview preparation, please consider:

• ⭐ Starring this repository
• 🔄 Sharing it with your network

• 💼 LinkedIn: linkedin.com/in/goswamikaushik
• 🌐 Portfolio: goswamikaushik.dev
• 🐙 GitHub: github.com/goswamikaushik

Built with ☕ and late nights · Good luck with your interviews! 🎉