Design a small subsystem that relies on memo, useMemo, useCallback

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Quick interview answer

Sketch components, data flow, failure modes, and metrics around memo, useMemo, useCallback. Example shape: Heavy DataGrid row component wrapped in memo; stable onSort callback via useCallback.

Detailed answer

Mini design using memo, useMemo, useCallback: • Components: API edge, worker/queue, store, and observability. • Data flow: request → memo, useMemo, useCallback-related path → response/async side effects. • Failure modes: timeouts, overload, partial dependency loss. • Metrics: latency, errors, saturation for the memo, useMemo, useCallback path. Guardrails: Profile first; memo leaf components receiving stable props from unstable parents. Parent context: React.memo skips re-render if props shallow-equal. useMemo caches computed value; useCallback caches function reference — helps memoized children avoid redundant renders.

Full explanation

Interviewers want a crisp architecture story anchored on memo, useMemo, useCallback, not a buzzword list. React.memo skips re-render if props shallow-equal. useMemo caches computed value; useCallback caches function reference — helps memoized children avoid redundant renders.

Follow-up questions

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Parent context — memo, useMemo, useCallback

React.memo skips re-render if props shallow-equal. useMemo caches computed value; useCallback caches function reference — helps memoized children avoid redundant renders.

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