Interview Q&A / React

INTERVIEW Q&A · 58 QUESTIONS

React interview questions

Rendering, state, hooks, keys and effects, explained with small examples.

  1. 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