FrontendHaltReact·Intermediate·Conceptual·1 min read
What's the main cost of a controlled input?
Short interview answer
Every keystroke updates React state, which triggers a re-render of the component holding that state — for a large form with many controlled fields, this can mean far more rendering work than the UI strictly requires.
Key takeaway
Explain the underlying mental model clearly, then support it with a concrete example and its trade-offs.