@radix-ui/react-use-is-hydrated

This is an exceptionally simple hook that returns a boolean indicating whether React has hydrated on the client. The entire implementation is basically a useState/useEffect wrapper - there's virtually no attack surface here. No network calls, no data processing, no dependencies beyond React itself.

From a security perspective, this is as safe as it gets: no supply chain risk beyond React, no input validation needed (it takes no inputs), no authentication concerns, and no error exposure issues. The code is trivial to audit. It solves the specific problem of avoiding hydration mismatches when you need client-only rendering for certain components.

The main limitation is its narrow scope - it does one thing only. You'll often need to pair it with Suspense boundaries or loading states. The lack of SSR detection on the server side means you still need to handle that case yourself, but that's by design.

This is an extremely lightweight utility hook that solves one specific problem: detecting when React has hydrated on the client. The implementation is dead simple - it returns false on initial server render and true after hydration completes. No surprises, no configuration needed, just works.

From a performance standpoint, it's essentially free. The hook uses a single useEffect with an empty dependency array and a boolean state toggle. Memory footprint is negligible, and there's no event listeners or timers to clean up. The package itself is tiny (under 1KB), so bundle impact is irrelevant.

The main practical use case is avoiding hydration mismatches when you need client-only rendering for certain components (like date formatters using local timezone, or features requiring window/document). It's more explicit than useEffect hacks and prevents the "flicker" of mismatched content. No retry logic or error handling needed since hydration is a one-time React lifecycle event.

This is an incredibly simple package that does exactly one thing: tells you when React has finished hydrating on the client. The API is literally just a hook that returns a boolean. Call `useIsHydrated()` and you get `false` during SSR/initial render, then `true` after hydration completes. It's as straightforward as it gets.

The learning curve is essentially zero - if you understand React hooks and hydration, you're already done. I've used this primarily to avoid hydration mismatches when dealing with client-only content like random IDs, localStorage values, or browser-specific features. The hook uses `useSyncExternalStore` under the hood, which means it's properly integrated with React 18's concurrent features and avoids the common pitfalls of naive hydration detection.

The main limitation is the lack of extensive documentation, but honestly, there's not much to document. The package is so focused that you'll spend more time reading this review than learning to use it. Error messages are standard React hooks errors - nothing special but nothing problematic either.