Learn how to limit concurrent API calls in JavaScript using async queues and promise batching — a crucial skill for scalable frontend systems.
Learn to build a robust retry mechanism for failed API calls, handling transient network errors gracefully.
Understand how JavaScript handles tasks, microtasks, and macrotasks — and how to control async execution order effectively.
Avoid inconsistent state in JavaScript apps by managing promise resolution order — essential for frontend data fetching and UI sync.
Prevent multiple token refreshes when parallel API calls fail — learn how to design a shared promise-based refresh mechanism.
Implement a robust deep-clone that handles Dates, RegExps, functions (optionally), and circular references — and know tradeoffs.
Use event delegation to reduce listeners, support dynamic elements, and improve performance — with patterns for delegation exceptions and delegation libraries.
Diagnose memory growth, understand mark-and-sweep, and apply strategies to prevent leaks in web apps and Node services.
Build a lightweight lazy-loading system that defers image downloads until they’re likely to be visible — without IntersectionObserver.
Move CPU-heavy tasks off the main thread with Web Workers and message passing — best practices, fallbacks, and performance considerations.
Learn how to create a custom debounce function that fires both on the leading and trailing edge — ideal for responsive search inputs.
Learn how memory leaks occur in single-page apps, how to diagnose them using Chrome DevTools, and how to fix common leak sources.
Implement efficient infinite scrolling using IntersectionObserver, batching, and virtualized rendering.
Prevent performance issues by throttling high-frequency events like resize or scroll using a custom JavaScript throttle implementation.
Process large datasets without freezing the UI using setTimeout, requestIdleCallback, or Web Workers.
Learn how to transform functions into reusable, smaller functions using currying and partial application.
Learn how to control function execution rates using debouncing and throttling for performance optimization.
Learn how event delegation lets you handle events efficiently by listening on a parent instead of multiple child elements.
Understand how JavaScript automatically frees memory using reachability and reference checks.
Learn how iterators define custom iteration behavior and how generators make writing them easier.