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JavaScript Core (Interview Prep)

A structured roadmap of the JavaScript fundamentals that matter most in frontend interviews. Start top-to-bottom.

Series: JavaScript Core

Progress: 0/25

Roadmap (25)

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  1. 1

    JavaScript Event Loop: Microtasks vs Macrotasks (Interview-Ready)

    A practical, interview-focused guide to the JS event loop: call stack, Web APIs, task queues, microtasks vs macrotasks, and common trick questions with real examples.

    ~10 min
  2. 2

    JavaScript Closures Explained (With Interview Questions)

    Closures in plain English: lexical scope, how closures work, common interview traps (loops + setTimeout), and practical use cases like memoization and data hiding.

    ~12 min
  3. 3

    JavaScript 'this' Explained: call/apply/bind + Arrow Functions

    A practical guide to 'this' in JavaScript: default binding, implicit binding, explicit binding (call/apply/bind), new binding, and how arrow functions change it.

    ~14 min
  4. 4

    JavaScript Hoisting + Temporal Dead Zone (var vs let/const)

    Interview-ready explanation of hoisting and the Temporal Dead Zone: what actually gets hoisted, why let/const behave differently, and common trick questions with outputs.

    ~12 min
  5. 5

    Promises Deep Dive: Chaining, Errors, all vs allSettled (Interview-Ready)

    A practical guide to JavaScript Promises for interviews: states, chaining rules, error propagation, finally, and when to use Promise.all vs allSettled vs race vs any.

    ~15 min
  6. 6

    Async/Await Pitfalls: Parallel vs Sequential (With Examples)

    Interview-focused async/await guide: how await works, common mistakes, parallelizing with Promise.all, error handling patterns, and when to avoid await-in-loop.

    ~12 min
  7. 7

    Memory Leaks in Frontend Apps: Causes, Detection, and Fixes (Interview-Ready)

    A practical guide to frontend memory leaks: the most common causes (listeners, timers, DOM refs, closures), how to detect them in Chrome DevTools, and how to fix them.

    ~15 min
  8. 8

    Map vs Set vs WeakMap vs WeakSet: When to Use Which (Interview-Ready)

    A practical guide to Map/Set and WeakMap/WeakSet: key differences, memory behavior, real use cases, and common interview questions with examples.

    ~12 min
  9. 9

    Debounce vs Throttle: Differences, Use Cases, and Implementations

    Interview-ready guide to debounce vs throttle: how they work, when to use each, and clean JavaScript implementations (with leading/trailing options).

    ~14 min
  10. 10

    JavaScript Prototypes & the Prototype Chain (Interview-Ready)

    A practical guide to prototypes in JavaScript: prototype chain, __proto__ vs prototype, new operator, inheritance patterns, and common interview questions.

    ~15 min
  11. 11

    JavaScript Modules: ESM vs CommonJS (import/export vs require)

    A deep, interview-ready guide to JavaScript modules: ESM vs CommonJS, named vs default exports, live bindings, top-level await, Node/browser differences, and common pitfalls.

    ~20 min
  12. 12

    JavaScript Equality & Type Coercion: == vs === (With Interview Traps)

    A deep, interview-ready guide to JavaScript equality: == vs ===, truthy/falsy, ToPrimitive coercion, Object.is, NaN, -0, and common output questions.

    ~22 min
  13. 13

    JavaScript Error Handling: try/catch, Custom Errors, and Patterns

    A deep, practical guide to error handling in JavaScript for frontend interviews: sync vs async errors, try/catch with async/await, custom error classes, cause, and user-friendly error patterns.

    ~20 min
  14. 14

    JavaScript Arrays for Interviews: map/filter/reduce + Time Complexity

    A deep, interview-ready guide to JavaScript arrays: core methods, common patterns, time/space complexity, mutation pitfalls, and practical questions with solutions.

    ~22 min
  15. 15

    JavaScript Objects: References, Cloning, and Immutability (Deep vs Shallow)

    A deep interview-ready guide to object references in JavaScript: shallow vs deep copies, structuredClone, JSON pitfalls, immutability patterns, and common bugs.

    ~20 min
  16. 16

    JSON in JavaScript: Serialization Pitfalls + Safe Parsing Patterns

    A deep guide to JSON in JavaScript for interviews and real apps: JSON.stringify behavior, undefined/functions, dates, BigInt, circular references, and safe parsing/validation patterns.

    ~18 min
  17. 17

    Browser Storage: localStorage vs sessionStorage vs IndexedDB (When to Use Which)

    A deep, interview-ready guide to browser storage: cookies vs Web Storage vs IndexedDB, quotas, security pitfalls (XSS), JSON patterns, and best practices for modern frontend apps.

    ~22 min
  18. 18

    Event Delegation in JavaScript: How It Works + Performance Patterns

    A deep, interview-ready guide to event delegation: bubbling/capturing, delegation patterns, performance benefits, common pitfalls, and clean implementations for real UIs.

    ~18 min
  19. 19

    CORS + Cookies + SameSite: Frontend Basics (Why Requests Fail)

    A deep, interview-ready guide to CORS for frontend developers: preflight, simple requests, credentials, cookies, SameSite, and how to debug common failures.

    ~22 min
  20. 20

    Browser Rendering Pipeline: Layout (Reflow) vs Paint vs Composite (Performance)

    A deep, interview-ready guide to how browsers render pages: DOM/CSSOM, render tree, layout (reflow), paint, compositing, GPU layers, and practical performance fixes.

    ~24 min
  21. 21

    HTTP Caching for Frontend: Cache-Control, ETag, and Practical Strategies

    A deep, interview-ready guide to HTTP caching: Cache-Control directives, ETag/If-None-Match, Last-Modified, CDN caching, and how frontend apps should leverage caching safely.

    ~24 min
  22. 22

    Service Workers + Offline Caching (Interview-Ready Guide)

    A deep, practical guide to Service Workers: lifecycle, caching strategies (cache-first, network-first, stale-while-revalidate), offline support, and common pitfalls.

    ~22 min
  23. 23

    Core Web Vitals (LCP, CLS, INP): Frontend Performance That Actually Matters

    A deep, practical guide to Core Web Vitals for frontend interviews: what LCP/CLS/INP measure, common causes, how to debug in DevTools, and high-impact fixes.

    ~24 min
  24. 24

    Accessibility Basics: Semantic HTML, ARIA, and Keyboard Navigation

    A deep, interview-ready accessibility guide: semantic HTML first, ARIA rules, focus management, keyboard support, and common mistakes that break screen readers.

    ~22 min
  25. 25

    Frontend Testing: Unit vs Integration vs E2E (What Interviewers Want)

    A deep, interview-ready guide to frontend testing: what to test, unit vs integration vs e2e tradeoffs, reliable patterns, and common anti-patterns.

    ~22 min

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