FrontendHaltReact·Intermediate·Coding·1 min read
What belongs in a ref?
Short interview answer
A ref holds a mutable value that persists across renders without triggering a render when changed. It fits DOM nodes, imperative handles, timer ids, or latest values used outside rendering. Visible UI data belongs in state.
Example
const intervalId = useRef(null);useEffect(() => { intervalId.current = setInterval(tick, 1000); return () => clearInterval(intervalId.current);}, []);Key takeaway
Explain the underlying mental model clearly, then support it with a concrete example and its trade-offs.