State

State is data that changes over time. In React, state drives the UI — when state updates, the component re-renders to reflect the new data.

useState Hook

useState is the most basic hook for managing state in functional components. It returns a state variable and a setter function.

useReducer Hook

For complex state logic involving multiple sub-values or when the next state depends on the previous one, useReducer is a better choice.

State Management Patterns

• Lifting state up to the nearest common ancestor
• Colocating state as close as possible to where it's used
• Using context for global state that doesn't change frequently
• Using external libraries (Zustand, Redux) for complex global state