React Hooks: useState & useEffect
In this lesson, you'll master React's two most essential hooks. We'll build real interactive components and understand the component lifecycle.
Key Concepts
- useState — Adds local state to a function component. Returns current state + updater function.
- useEffect — Runs side effects after render. Replaces componentDidMount and componentDidUpdate.
- Dependency Array — Controls when the effect re-runs. Empty array = run once on mount only.
- Cleanup Function — Return a function from useEffect to clean up subscriptions or timers.