react-8

Difference Between useState() and useEffect() in React

useState	useEffect
Used to manage state	Used to perform side effects
Stores data	Runs code after rendering
Causes re-render when state changes	Doesn't store data
Returns state and updater function	Executes a callback function

1. What is useState()?

useState() is used to create and manage state in a functional component.

What Happens?
Initial value = 0
Clicking button updates state
Component re-renders
Updated value appears on screen

What is useEffect()?

useEffect() is used to perform side effects after a component renders.

Side Effects Examples
API calls
Fetching data
Timers
Event listeners
DOM manipulation