Pretty classic frontend question but I second-guessed myself mid-answer.
Start by acknowledging the problem: firing a request per keystroke is inefficient and can cause race conditions. Then describe a debouncing strategy as the primary solution, and optionally mention throttling or request cancellation for completeness. Finally, discuss trade-offs and edge cases like immediate feedback for empty queries or handling IME composition.
Pro tip: Mention that debouncing should be combined with request cancellation (e.g., AbortController) to prevent out-of-order responses, and that you might debounce the network call but not the UI update for a responsive feel.
Explain why firing a request on every keystroke is bad: excessive network calls, server load, and potential race conditions where older responses overwrite newer ones.
Describe debouncing as the go-to solution: wait for a pause in typing (e.g., 300ms) before sending the request. Mention that this reduces calls significantly while still feeling responsive.
Mention throttling as an alternative that limits requests at a steady rate, and discuss combining debouncing with request cancellation (e.g., AbortController) to handle in-flight requests when a new one is triggered.
Talk about immediate feedback for empty queries, handling IME composition events, and the trade-off between responsiveness and server load. Also mention that debouncing can be applied to the network call but not the UI filtering if data is local.
Conclude by emphasizing that the goal is to balance performance with a smooth user experience, and that the exact delay should be tuned based on context (e.g., 200-500ms).
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.