Deep Dives into Frontend Development
Explore in-depth articles on JavaScript fundamentals, React patterns, system design, and interview preparation
Arrow Functions Hoisting in JavaScript vs React
Understand why arrow functions aren't hoisted like regular functions, the Temporal Dead Zone (TDZ), and why React doesn't seem to care about hoisting. Learn with practical code examples.
Why JavaScript is Weakly Typed
Understand the difference between strong and weak typing, how type coercion works in JavaScript, and why this matters in interviews. Learn best practices to avoid common pitfalls.
JavaScript is Single-Threaded: How Hoisting Works
If JavaScript is single-threaded, why doesn't it execute sequentially? Learn about the two-phase execution model, the event loop, and why hoisting doesn't violate single-threading.
Is JavaScript Interpreted or Compiled?
JavaScript uses JIT compilation, not pure interpretation. Learn how V8, JavaScriptCore, and SpiderMonkey compile and optimize your code at runtime.
React's Diffing Algorithm: How O(n) is Possible
Tree comparison is typically O(n²) or O(n³). Discover how React achieves O(n) complexity through three key assumptions about component patterns.
How Google Keeps You Logged In Across Domains
Understand how logging into Gmail automatically logs you into YouTube, Calendar, and other Google services using domain cookies and cross-domain authentication.
Why Does My React Callback See Old State? The Stale Closure Problem
A practical model for stale closures in timers, event listeners, async requests, and memoized callbacks - plus the patterns that actually fix them.
What Actually Happens After You Call setState in React?
Follow a state update from an event handler to scheduling, rendering, committing, effects, batching, and the browser paint.
Your React Fetch Worked Until Users Typed Fast: Race Conditions Explained
Build a reliable request flow by handling cancellation, stale responses, loading states, retries, and cache ownership.
Why React Keys Can Move Your Input Cursor to the Wrong Row
Keys are React's identity system. Learn why index keys break editable lists, animations, component state, and optimistic updates.
Where Should This State Live? A React State Ownership Framework
Choose deliberately between local, lifted, URL, server, and global state using a practical decision process.
Why Does a Promise Run Before setTimeout? The Event Loop in a React App
Understand tasks, microtasks, browser rendering, React updates, and why timing assumptions create frontend bugs.
Build a React Search That Feels Instant Without Lying to the User
A complete search design: controlled input, debouncing, URL state, cancellation, keyboard support, loading, empty, and error states.
Stop Treating useEffect Like componentDidMount
Use effects to synchronize external systems, avoid derived-state effects, and reason correctly about dependencies and cleanup.
How JavaScript Modules Work: The Circular Dependency That Broke Production
Go beyond import syntax with module initialization, live bindings, circular dependencies, ESM versus CommonJS, tree shaking, and code splitting.
The App Feels Slow: A Frontend Performance Investigation Playbook
Turn a vague performance complaint into evidence with Core Web Vitals, traces, React profiling, bundle analysis, and measurable fixes.