System Design

Design an Autocomplete / Search UI

mediumperformance

Design an Autocomplete / Search UI

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Key Challenges

  • ·Debounced API calls without excessive network requests or jank
  • ·Keyboard navigation (arrows, enter, escape, tab) with proper focus management
  • ·Highlighting matched search terms in results
  • ·Caching and deduplication of results to avoid duplicate fetches
  • ·Full ARIA combobox accessibility (screen readers, live regions, activedescendant)

Key Takeaways

  • Never fetch on every keystroke — 250-300ms debounce + cache by query string is mandatory.
  • Use a headless AutocompleteManager (plain class) + Zustand store to keep rapid updates performant.
  • Keyboard navigation + ARIA combobox pattern is what separates junior from senior implementations.
  • Client-side result highlighting (mark or regex) and instant preview with no layout shift.
  • Always use AbortController to cancel stale requests and prevent race conditions.