All things design and code.
Featured
·5 min read
Server State Management and How TanStack Query Fits In
If you've been reading the React Foundations series and Alex Chen keeps mentioning TanStack Query as the replacement for useEffect data fetching — and you've been wondering what it actually does and why it exists as a category of its own — this is that explanation. With a real user profile card you can build today.
Featured
·5 min read
React.memo, What Is It Actually Doing?
If you've been reading the React Foundations series and seen React.memo appear in performance-related articles without a clear explanation of what it actually wraps and why — this is that explanation. With a real notification feed component you can build today.
Featured
·4 min read
useRef: The Hook That Remembers Without Re-Rendering
If you've been following the React Foundations series and seen useRef appear in custom hooks and component implementations without a clear explanation of what it actually holds — this is that explanation. With a real autosaving text editor widget you can build and use today.
Featured
·3 min read
Make Use of useMemo Like You Mean It
If you've been following the React Foundations series and kept seeing useMemo appear alongside useCallback without a clear explanation of when it actually helps — this is that explanation. With a real filterable product list you can build and use today.
Featured
·3 min read
Did You Know useCallback Can Actually Do This?
If you've been reading the React Foundations series and kept seeing useCallback appear in custom hooks and effect dependency arrays without a clear explanation of what it actually does — this is that explanation. With a real dropdown component you can build today.
Featured
·4 min read
useEffect, What Is It Really?
If you've been reading the React Foundations series on DesignDev.io and kept seeing useEffect appear without a full explanation of what it actually is — this is that explanation. Real examples, real UI components, no hand-waving.
Featured
·5 min read
We're Not a Blog. We're a Team.
DesignDev.io isn't one person's opinion column. It's nine writers covering everything from React internals to freelance rate cards — and one founder explaining what they all missed. Here's who we are and why we built this.
More Stuff
·4 min read
Why React.memo Doesn't Always Help (And When It Does)
Wrapping a component in React.memo and finding it still re-renders on every parent render is one of the most common React performance frustrations. The fix is almost always the same — and it has nothing to do with memo itself.
Alex Chen
·3 min read
Building a Fully Accessible Modal from Scratch in React
Most modal implementations look right but fail accessibility checks. Focus trapping, scroll locking, ARIA attributes, and keyboard handling — each one is a trap for the unwary. Here's a complete implementation that gets all four right, including the iOS Safari scroll lock bug nobody warns you about.
Alex Chen
·5 min read
React Reconciliation Explained: What the Diffing Algorithm Actually Does
Most React developers have a working mental model of the virtual DOM. Most of those mental models are imprecise enough to cause real bugs. Here's what React's diffing algorithm actually does — and the two heuristics that explain why key, memo, and component type all matter.
Alex Chen
·5 min read
How to Lazy-Load Components the Right Way (And Avoid the Trap)
React.lazy and Suspense are the right tools for code splitting in React — but lazy-loading the wrong things creates waterfalls that hurt more than they help. Here's the granularity rule that makes code splitting actually improve performance.
·3 min read
Compound Components: The Design Pattern That Changed How I Build UIs
Most component APIs grow boolean props until they're unreadable. Compound components are the pattern that stops that from happening — by making the component's structure part of its API. Here's how it works and when to reach for it.
Alex Chen
·3 min read
TypeScript Generics in React: The Patterns You'll Use Every Week
TypeScript generics in React feel intimidating right up until the moment they don't. The syntax is the hard part — the patterns themselves are straightforward once you see them three or four times. Here are the five you'll reach for every week.
Alex Chen
·6 min read
The Testing Pyramid: What Is It Really?
If you've been reading Mira Halsted's testing series and kept seeing references to "the testing pyramid" and "test budget" without a clear picture of what they actually mean in a real project — this is that picture. With a real component suite you can use to see each layer in action.
Muhammad Athar
·3 min read
How to Test Custom Hooks with React Testing Library
Custom hooks encapsulate logic you care about keeping correct. Testing them directly — not through a component — is cleaner, faster, and catches regressions earlier. Here's the complete renderHook pattern with three real hook tests you can adapt today.
Alex Chen
·4 min read
Controlled vs Uncontrolled Components: The Decision You Keep Making Wrong
Most React developers default to controlled inputs for everything. That's not wrong — but it's not always right either. The decision between controlled and uncontrolled components has real performance and complexity consequences. Here's the framework that makes it obvious.
Alex Chen
Showing 1 - 9 of 16 posts