Posts about React

React callback refs: what, why, and why not

Callback refs are a small React feature that solve real problems when object refs fall short. Here's how they work, when they shine, and when to avoid them.

When I reach for React's memo, useMemo and useCallback

A lot of the memoisation in a React codebase does nothing, and some of it costs more than it saves. These are the few cases where I still use it.

How I type React components in TypeScript

After a few years of typing React components I'm down to a handful of shapes, and I let the compiler infer the rest. React.FC isn't one of them anymore.

Fixing a laggy search filter with useDeferredValue

Typing into the filter above a long table felt like typing over a bad SSH connection. React 18 has a hook for exactly this and the fix was one line. Well, two.

Moving my tests from Jest to Vitest

Eight months ago I left the tests behind when I moved to Vite. Moving them took an evening. Reading them took longer, because most of them tested the wrong thing.

Why React 18 runs your effects twice

We upgraded to React 18 and every request in the dev tools showed up twice. React does that on purpose, as a test, and our effects were failing it.

Discriminated unions: the TypeScript feature I'd teach first

Three booleans for one request gave us a spinner on top of an error message. One union with a status field fixed it, and now the compiler tells me when I forget a case.

Moving a Create React App project to Vite

Create React App 5 landed this week after a year of waiting, and I still moved my side project to Vite. It took an evening, mostly spent renaming things.