Most engineers prepare for JavaScript interviews with tutorials. Senior engineers study under pressure.

This ebook gives you 41 hand-picked machine coding problems — the exact kind that separate staff-level candidates from the rest in frontend-heavy interviews at startups, unicorns, and top product companies.

This is not a beginner's guide. Every problem is chosen because it tests how you think, not just whether you can recall syntax.

What makes this different:

Every solution goes beyond "here's the code." You get the naive approach, the production-grade solution, the edge cases that trip up 90% of candidates, and the interviewer commentary that tells you exactly what they're evaluating.

Topics covered across 41 problems:

Closures & functional patterns — Currying, Currying with Placeholders, Pipe Function, Custom Reduce, Lodash Memoize

Async & concurrency — Debouncing with Cancel & Flush, Throttling, Running Tasks in Parallel and Series, Map Limit, Task Runner with Concurrency Control, Auto Retry with Exponential Backoff, Async Performance Measurement

JavaScript internals — Custom Promise Implementation, Promise.allSettled Polyfill, Custom Call/Apply/Bind, Array Filter Polyfill, Custom JSON Stringify, Promisify Async Callback

Data structures — LRU Cache, Event Emitter, Custom History, Custom SetInterval, Longest Common Prefix

Real-world system design problems — API Client with Token Refresh, Feature Flag Service with Caching, Rate Limiter, Event Logging Client, Cache API Call, Uber Driver Chainable API

DOM & React — Virtual DOM Serialization & Deserialization, React ClassName, Get Lodash

Business logic problems — Credit Card Masker, Account Comparison, Max Profit

And many more inside

Who this is for:

Engineers at 4–10 years of experience targeting Senior (L5/L6) or Staff roles. Frontend engineers at companies where JavaScript is taken seriously — not just "can you center a div" interviews. Anyone who has failed a machine coding round and wasn't sure why.

Who this is NOT for:

Complete beginners to JavaScript. Engineers looking for DSA / LeetCode-style algorithm prep. People who want a quick cheat sheet without understanding the solutions.

What you get:

A structured PDF ebook you can work through in 4–6 weeks of focused preparation. Each chapter is self-contained — jump to any topic you're weak on. Solutions are written in clean, modern JavaScript with TypeScript annotations where relevant.

One purchase. Instant download. No subscription.