React
State
Data a component manages itself and that changes over time, triggering a re-render when updated.
Reviewed by the RadarTrek editorial team · June 2026
State is data that lives inside a component and can change — a form input's value, whether a menu is open, a counter. React's useState hook lets a component declare state and update it; whenever state changes, React automatically re-renders the component to reflect the new value.
Why it matters
- —State is what makes a UI interactive instead of static — without it, nothing on screen could change.
- —Updating state never mutates it directly — you always call the setter function React gives you.
- —Most React bugs trace back to a misunderstanding of when and how state updates trigger re-renders.
Where to learn this
🎓
useState: Component Memory
React Fundamentals course
This is the exact lesson that covers this term in depth — with examples, diagrams, and a hands-on exercise.