Interview Q&A / React
React interview questions
Rendering, state, hooks, keys and effects, explained with small examples.
Prefer rapid revision? Practise React short interview answers →
- What is the difference between useMemo and useCallback, and when should you not use them?
useMemo caches the result of a calculation, and useCallback caches a function itself, both until their dependencies change. Use them for expensive calculations or to keep values stable for memoized children or effect dependencies; skip them for cheap work, where they only add complexity.
IntermediateIn-depth3 min read