ReactInterview preparation
Foundation·Concept·2 min read

Props vs state: what is the difference?

Practice this question

Definition:

Props are values a parent supplies to a component, while state is data React remembers for a component across renders. Both influence the UI, but a component should not change its received props directly. State updates request a new render so the screen can reflect the new data.

Key points:

  • Props are inputs from a parent; treat them as read-only.

  • State is component data that can change over time.

  • Lift shared state to the nearest common parent when needed.

  • Use one clear owner for shared data; copying the same prop into local state without a synchronization rule often creates stale values.

Interview point:

  • Explain who owns the data and who is allowed to request a change, rather than only saying props are external and state is internal.
Adapted from 06_REACT_NEXTJS.md · “Props vs state: what is the difference?”. Code examples are study fragments. Difficulty and core labels are editorial estimates; version-specific behavior should be checked against your project.