Answer
useMemo runs again only when its dependencies change. If dependencies include unstable references, memoization becomes ineffective.
Quick Answer
useMemo re-runs when any value in its dependency array changes (using Object.is comparison). If dependencies are primitive values (strings, numbers), React can accurately detect changes. If dependencies are objects or arrays, a new reference always triggers re-computation — even if contents are the same. Stabilize object dependencies with their own useMemo.
S
SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
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Source: SugharaIQ