Recent posts tagged react

Here is a pattern I see in almost every React codebase I read: const fullName, setFullName = useState''; useEffect => { setFullNamefirstName + ' ' + lastName; }, firstName, lastName; It works. It also renders twice every time a name changes, sh...

What is the Drag and Drop API? The Drag and Drop API is a built-in browser capability that allows web applications to make elements on a webpage interactive through dragging and dropping. Instead of forcing users to click buttons or select items fr...

Every React codebase of a certain age has one: the legacy Redux store. Hundreds of thunk actions, manually managed loading flags, per-feature cache invalidation, and a polling timer per data type pulling the full payload whether anything changed or n...

In Part 5 of our engineering serieshttps://www.datalaria.com/en/posts/app-lifeopspart5deploymobilepwa/, we achieved a major milestone: deploying the entire LifeOps architecture 24/7 in production at zero cost $0/month by combining Netlify, Render, an...

You upgrade from Next.js 14 to 15. The app compiles, the tests pass, nothing visibly breaks. A week later your database bill is higher, your pages feel slower, and your Time to First Byte graph has a step in it that lines up exactly with the deploy. ...

Modern web applications generate a continuous stream of user activities. Users log in, update their profiles, create records, upload files, change permissions, and perform many other actions throughout the day. In a small application, tracking these ...

Modern web applications often need to handle large amounts of structured data. Whether you are building a customer relationship management CRM platform, an inventory management system, an employee dashboard, or an e-commerce application, users freque...

Introduction React is a powerful JavaScript library, but as applications grow, performance bottlenecks can arise. Unnecessary re-renders, inefficient state management, and large bundle sizes can lead to slow applications. This guide covers practica...

You format a date in a component. It looks right on your laptop. Then a user in another country opens the page and either sees a console full of hydration errors, or worse, sees nothing wrong at all and reads the wrong time. I live in a timezone tha...

What is the Critical Path in Performance Budgets? A performance budget is a set of strict limits agreed upon by a web development team to cap resource sizes, file counts, or loading speeds. The critical path—often called the Critical Rendering Path...

A mobile menu that pops in and out works, but it feels unfinished. In this article we turn it into a drawer that slides in from the right with a fading backdrop, using only Tailwind classes and no animation library. We also keep it usable for keyboar...

You add a small search box to your navbar. It reads the query string, so you reach for useSearchParams. Everything works in next dev. You push, the deploy fails, and the build log says: useSearchParams should be wrapped in a suspense boundary at pag...

Here is a bug report you will eventually get: "The signup form told me what was wrong on your machine, but on the live site it just says something went wrong." Nothing is broken. Next.js is doing this on purpose. But the code that triggers it looks ...

A header that works on a phone and on a desktop is one of the first things every site needs. In this part of the TanStack Start Basics series, we'll build one with inline links on wide screens, a hamburger menu on small ones, and a few accessibility ...

Almost every Tailwind developer hits this exact bug once, usually right after a deploy, and the confusing part is that nothing about it looks wrong in the code, nothing throws an error, and it worked completely fine five minutes earlier on the same m...

This is the kind of bug that goes from "works perfectly in every test" to "actively leaking one customer's data to another customer" without a single code change in between, purely because of how caching and personalization interact in a way that isn...

Isolate to Elevate: Why Component Testing in Isolation Saves Your Codebase Component testing in isolation is a software verification strategy where an individual piece of an application—such as a button, user profile card, or navigation bar—is eval...

Stop Rewriting Browser Fingerprinting Logic in React: Meet useFingerprint Browser fingerprinting is an interesting technique for understanding whether multiple browser visits might come from the same browser environment. But if you're building Reac...

Have you ever looked at a React component and thought: “Maybe I should wrap this function with useCallback, this calculation with useMemo, and the component with React.memo?” You're not alone. Memoization is one of the most frequently discussed Re...

This is one of those bugs where the code looks completely reasonable, passes every manual test you'd naturally think to run, and still ships with a real defect that only shows up under a specific, very common usage pattern: someone typing faster than...