React

JS Library for creating UI.


JSX

JavaScript Extension Syntax

It lets us write HTML directly inside JS.

JSX -----> babel ----->   JS



https://vitejs.dev/guide/

  1. npm create vite@latest
  2. npm install
  3. npm run dev





Writing Markup in JSX Rule:-

1. Return a single root element

2. Close all the tags

3. camelCase most of the things


React Fragment

Fragments let you group a list of children without adding extra nodes to the DOM.






onClick

onMouseHover

event.preventDefault()  - ye form ko submit hone ke bad default behavior ko stop kar deta hai, ex- page refresh


State in React

The state is a built-in React object that is used to contain data or information about the component.
A component's state can change over time; whenever it changes, the component re-renders.


Hooks

Hooks were a new addition in React 16.8.
They let you use state and other React features without writing a class.



nayi value agar purani value ko use kare to callback use karenge

agar componet change nahi hoga setCount me to React detect kar lega or dobara render nahi karwayega, react apna resource save karega

useState me agar function pass kar rahe ha to hamesa [useState(function-name)] kake ke call kare, nahi to [useState(function-name())] es trah likhne se wo har bar call hota rahega ,hamko to bas ek bar chiye value initillize karne ke liye-
 ex- math.random vala example yaad karoo