Follow-up · depth 9
Compare memo, useMemo, useCallback with a common alternative in a design review
Compare memo, useMemo, useCallback with a common alternative in a design review
Answers use simple, clear English.
Quick interview answer
Compare memo, useMemo, useCallback vs the usual alternative on complexity, latency, failure modes, and ops cost. Pros: Targets expensive subtrees without manual shouldComponentUpdate. Cons: Premature optimization — memo has comparison cost; stale closures if deps wrong.
Detailed answer
Design-review comparison for memo, useMemo, useCallback: Axes: correctness, latency, throughput, complexity, operability. From the topic: Pros: Targets expensive subtrees without manual shouldComponentUpdate. Cons: Premature optimization — memo has comparison cost; stale closures if deps wrong. Recommendation: pick memo, useMemo, useCallback when its strengths match the SLO; otherwise choose the alternative and say why. 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
Show a clear decision framework, not “it depends” with no criteria. 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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