Blog

A virtual DOM is a data structure plus four functions, about 150 lines. Build h, createElement, diff and patch — then measure where "minimal DOM operations" is true and where it quietly isn't.

HOCs didn't die with hooks. React.memo, Redux connect, and half your favorite libraries still use them. Learn to write type-safe HOCs and when to reach for the pattern.

Conditional types and mapped types let you write types that compute — filtering keys, extracting nested types, and deriving new shapes from old ones without duplication.

Node.js is single-threaded — but Worker Threads let you move CPU-heavy tasks off the event loop so your server stays responsive under real load.

React or Vue for a new dashboard? A comparison of the component model, reactivity, state management, TypeScript story and hiring reality — with the invented benchmark numbers left out.

React 18+ lets you mark state updates as non-urgent so expensive re-renders stop blocking inputs. Here's exactly when to use startTransition, useTransition, and useDeferredValue.

TypeScript ships with 15+ utility types that let you derive new types from existing ones. Here's the full toolkit with the production patterns you'll actually reach for.

Build Node.js's EventEmitter from scratch in 100 lines. Learn why listener removal requires saved references, how once() wraps callbacks, and what that MaxListenersExceededWarning actually means.

Sliding window maximum is the classic follow-up to every sliding window problem. Learn the monotone deque pattern in JavaScript with LeetCode 239, 1438, and 1696.