1.What is JSX in React?

JSX stands for JavaScript XML.

It is a syntax extension for JavaScript used in React to write HTML-like code inside JavaScript.

Why Use JSX?

JSX makes it easier to build UI in React by letting you write components using syntax that looks like HTML, but is actually converted to JavaScript behind the scenes.

2.What is component in react

In React, a component is a reusable, self-contained piece of UI — like a function or class — that returns JSX (HTML-like syntax) to describe what should appear on the screen.

🧠 Simple Definition

A component is a function or class that returns React elements (usually written in JSX) to be rendered on the web page.

3. what is props state hook in react

Props are inputs to a component.

  Used to pass data from parent to child component.

  Read-only – the child component cannot modify props.

2️⃣ State

💡 What it is:

• State is local data that a component manages itself.
• State can change over time, usually in response to user actions.
• State changes cause the component to re-render.

import { useState } from ‘react’;

function Counter() {

const [count, setCount] = useState(0);

return (

<>

<p>Count: {count}</p>

<button onClick={() => setCount(count + 1)}>Increment</button>

</>

);

}

Hooks

💡 What it is:

• Hooks are functions that let you “hook into” React’s features (state, lifecycle, etc.) in functional components.
• Hooks are used only inside functional components (not class components).

• Common React Hooks:

4. Diff between angular and react

• Angular: A full-fledged framework (developed by Google). It comes with routing, state management, form handling, HTTP client, etc. → batteries included.
• React: A UI library (developed by Meta/Facebook). Focuses only on building UI components. For routing, state management, etc., you add third-party libraries (e.g., React Router, Redux).

🔹 2. Language

• Angular: Uses TypeScript by default (strictly typed).
• React: Uses JavaScript (with optional TypeScript).

🔹 3. Learning Curve

• Angular: Steeper → you need to learn concepts like modules, decorators, dependency injection, RxJS (observables).
• React: Easier to pick up → learn JSX, props, state, hooks. More flexible but requires picking additional libraries for big projects.

🔹 4. Performance

• Angular: Uses a real DOM (with change detection) but optimized with zone.js and ahead-of-time (AOT) compilation.
• React: Uses a Virtual DOM that efficiently updates only the changed parts → often faster for frequent UI updates.

🔹 5. Architecture

• Angular: Opinionated, MVC/MVVM-style architecture. Code is more structured.
• React: Flexible, unopinionated. You can structure your app however you want.

🔹 6. Ecosystem

• Angular: Provides almost everything out of the box (routing, forms, HTTP, testing).
• React: Huge ecosystem, but you need to choose packages for routing, state management, forms, etc.

🔹 7. Use Cases

• Angular: Good for large-scale enterprise apps (e.g., dashboards, CRMs, ERPs) where strict structure helps big teams.
• React: Good for dynamic, fast UIs (e.g., single-page apps, social media, e-commerce) where flexibility is needed.

5.what is == and === in react?

In React, == and === are JavaScript operators. React itself doesn’t define them—it simply uses JavaScript expressions.

The important difference is:

  type: "h1",
  props: {
    children: "Hello"
  }
}