Follow-up · depth 4
What trade-offs come with memo, useMemo, useCallback?
What trade-offs come with memo, useMemo, useCallback?
Answers use simple, clear English.
Quick interview answer
Pros: Targets expensive subtrees without manual shouldComponentUpdate. Cons: Premature optimization — memo has comparison cost; stale closures if deps wrong.
Detailed answer
Trade-offs for memo, useMemo, useCallback: Pros: Targets expensive subtrees without manual shouldComponentUpdate. Cons: Premature optimization — memo has comparison cost; stale closures if deps wrong. Decision rule: choose memo, useMemo, useCallback when the benefits outweigh operational cost for your SLO. Parent context: Logic: 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
Strong answers state both sides and when you would pick an alternative. Pros: Targets expensive subtrees without manual shouldComponentUpdate. Cons: Premature optimization — memo has comparison cost; stale closures if deps wrong.
Follow-up questions
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Parent context — memo, useMemo, useCallback
Logic: 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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