JavaScript Guide: Basic → Advanced 🚀 with Suraj Gehlot

One PDF to crack your JavaScript interview 🚀

I compiled a 110-page guide that takes you from basics to advanced, the way interviewers actually ask. Not just definitions: every topic explains HOW JavaScript works, with code and real interview questions.

📘 WHAT'S INSIDE (11 parts)

1️⃣ How JavaScript Actually Works

→ JS engine, runtime, execution context, call stack

→ Memory heap & garbage collection

→ Event loop (the most asked topic), sync vs async, single-threaded

→ How the browser renders a page (Critical Rendering Path)

→ Lexical environment, scope & scope chain

2️⃣ Fundamentals

→ Data types, hoisting, Temporal Dead Zone

→ var vs let vs const, null vs undefined, == vs ===

→ Type coercion, typeof traps, pass by value vs reference, strict mode

3️⃣ Functions, Closures & this

→ Arrow functions, IIFE, callbacks, higher-order & pure functions

→ Closures with real use cases, currying, the 4 rules of "this"

→ call, apply, bind explained with code

4️⃣ Objects, Prototypes & Classes

→ Prototype chain, inheritance, ES6 classes, shallow vs deep copy

5️⃣ Arrays, Map, Set & Collections

→ map / filter / reduce, Map vs Object, Set, WeakMap

6️⃣ Asynchronous JavaScript

→ Callbacks → Promises → async/await

→ Microtasks vs macrotasks, with output-based questions

7️⃣ Browser, DOM, Storage & Web APIs

→ Event bubbling & delegation, localStorage vs sessionStorage vs cookies

8️⃣ Advanced Concepts, Tooling & Patterns

→ Debounce, throttle, memoization, modules, design patterns

9️⃣ 50 "Guess the Output" Questions, each with an explanation

🔟 43 Coding Problems with solutions

1️⃣ 1️⃣ ES6+ Features & a final revision sheet

🛠 MUST-KNOW POLYFILLS

bind, call, apply, Promise.all, allSettled, race, any, debounce, throttle

🎯 WHO IT'S FOR

→ Freshers & 0–5 YOE frontend developers preparing for interviews

→ Anyone who wants to finally understand closures, "this" and the event loop

→ React developers who want stronger JavaScript fundamentals

✅ WHAT YOU GET

→ 110-page PDF with 107 interview questions and detailed answers

→ Clean code examples and "Most asked" tags so you know what to focus on

→ Instant download, read on laptop, tablet or phone

Prepared by Suraj Gehlot, Frontend Engineer

💬 Want to practise live? Book a mock JavaScript interview with me.