A Beginner’s Guide to React: Getting Started

June 24, 2025

Introduction to React

React is one of the most popular JavaScript libraries for building user interfaces, particularly single-page applications (SPAs). Developed and maintained by Facebook (now Meta), React allows developers to create reusable UI components, making web development faster and more efficient.

If you’re new to React, this guide will walk you through everything you need to know—from setting up your first React project to understanding core concepts like components, state, and props.

Why Learn React?

High Demand in the Job Market: React is widely used by companies like Facebook, Netflix, Airbnb, and Instagram.
Reusable Components: Write once, use multiple times.
Virtual DOM: Improves performance by minimizing direct DOM manipulation.
Strong Community Support: Extensive documentation, tutorials, and third-party libraries.

Prerequisites for Learning React

Before diving into React, you should have a basic understanding of:

HTML & CSS (for structuring and styling web pages)
JavaScript (ES6+) (including arrow functions, destructuring, modules, and classes)
Node.js & npm/yarn (for package management)

Setting Up Your First React Project

1. Install Node.js

React requires Node.js to run JavaScript outside the browser. Download and install it from Node.js official website.

2. Create a React App

The easiest way to start a React project is by using Create React App (CRA), a toolchain that sets up a modern React project with zero configuration.

Run the following command in your terminal:

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npx create-react-app my-first-react-app

(Replace my-first-react-app with your project name.)

3. Navigate to Your Project

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cd my-first-react-app

4. Start the Development Server

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npm start

This will open your React app in the browser at http://localhost:3000.

Understanding React Project Structure

When you create a React app, you’ll see the following folder structure:

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my-first-react-app/
├── node_modules/ (All dependencies)
├── public/ (Static files like HTML)
│   ├── index.html (Main HTML file)
│   └── ...
├── src/ (React components & logic)
│   ├── App.js (Main React component)
│   ├── index.js (Entry point)
│   └── ...
├── package.json (Project dependencies)
└── ...

Core Concepts of React

1. Components

React applications are built using components—reusable, self-contained pieces of UI.

There are two types of components:

Functional Components (Written as JavaScript functions)
Class Components (Written as ES6 classes, less common now)

Example of a Functional Component

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import React from 'react';

function Greeting() {
  return <h1>Hello, React!</h1>;
}

export default Greeting;

Example of a Class Component

jsx

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import React, { Component } from 'react';

class Greeting extends Component {
  render() {
    return <h1>Hello, React!</h1>;
  }
}

export default Greeting;

2. JSX (JavaScript XML)

JSX is a syntax extension for JavaScript that allows you to write HTML-like code inside JavaScript.

Example:

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const element = <h1>Hello, JSX!</h1>;

3. Props (Properties)

Props allow you to pass data from parent to child components.

Example:

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function Welcome(props) {
  return <h1>Hello, {props.name}</h1>;
}

// Usage
<Welcome name="John" />

4. State

State is used to manage data that changes over time within a component.

Using State in Functional Components (Hooks)

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import React, { useState } from 'react';

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

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
}

Using State in Class Components

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import React, { Component } from 'react';

class Counter extends Component {
  constructor(props) {
    super(props);
    this.state = { count: 0 };
  }

  increment = () => {
    this.setState({ count: this.state.count + 1 });
  };

  render() {
    return (
      <div>
        <p>Count: {this.state.count}</p>
        <button onClick={this.increment}>Increment</button>
      </div>
    );
  }
}

5. Lifecycle Methods (Class Components) & useEffect (Functional Components)

Lifecycle methods are used in class components to perform actions at different stages of a component’s life (e.g., when it mounts, updates, or unmounts).

In functional components, the useEffect hook replaces lifecycle methods.

Example of useEffect:

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import React, { useState, useEffect } from 'react';

function Timer() {
  const [seconds, setSeconds] = useState(0);

  useEffect(() => {
    const interval = setInterval(() => {
      setSeconds(prevSeconds => prevSeconds + 1);
    }, 1000);

    return () => clearInterval(interval); // Cleanup
  }, []);

  return <div>Seconds: {seconds}</div>;
}

Handling Events in React

React events are similar to DOM events but use camelCase syntax.

Example:

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function ButtonClick() {
  const handleClick = () => {
    alert('Button clicked!');
  };

  return <button onClick={handleClick}>Click Me</button>;
}

Conditional Rendering

You can conditionally render components using JavaScript operators like if, &&, or ternary operators.

Example:

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function Greeting({ isLoggedIn }) {
  return (
    <div>
      {isLoggedIn ? <h1>Welcome back!</h1> : <h1>Please log in.</h1>}
    </div>
  );
}

Lists and Keys

When rendering lists, each item should have a unique key prop for performance optimization.

Example:

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function TodoList() {
  const todos = ['Learn React', 'Build a project', 'Deploy app'];

  return (
    <ul>
      {todos.map((todo, index) => (
        <li key={index}>{todo}</li>
      ))}
    </ul>
  );
}

React Router for Navigation

To handle multiple pages in a React app, use React Router.

Installation

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npm install react-router-dom

Example Usage

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import { BrowserRouter as Router, Route, Link, Routes } from 'react-router-dom';

function Home() {
  return <h1>Home Page</h1>;
}

function About() {
  return <h1>About Page</h1>;
}

function App() {
  return (
    <Router>
      <nav>
        <Link to="/">Home</Link>
        <Link to="/about">About</Link>
      </nav>
      <Routes>
        <Route path="/" element={<Home />} />
        <Route path="/about" element={<About />} />
      </Routes>
    </Router>
  );
}

Fetching Data in React

You can fetch data from APIs using fetch or libraries like axios.

Example with useEffect:

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import React, { useState, useEffect } from 'react';
import axios from 'axios';

function FetchData() {
  const [data, setData] = useState([]);

  useEffect(() => {
    axios.get('https://api.example.com/data')
      .then(response => setData(response.data))
      .catch(error => console.error(error));
  }, []);

  return (
    <ul>
      {data.map(item => (
        <li key={item.id}>{item.name}</li>
      ))}
    </ul>
  );
}

Styling in React

You can style React components using:

Inline Styles
CSS Modules
Styled Components
Tailwind CSS

Example with CSS Modules:

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import styles from './App.module.css';

function App() {
  return <h1 className={styles.title}>Hello, React!</h1>;
}

Deploying a React App

To deploy your React app, you can use:

Vercel
Netlify
GitHub Pages
Firebase Hosting

Steps for Vercel Deployment:

Run npm run build to create a production build.
Drag and drop the build folder to Vercel.

Best Practices for React Development

Keep Components Small & Reusable
Use Functional Components with Hooks
Avoid Direct State Mutations
Use PropTypes or TypeScript for Type Checking
Optimize Performance with React.memo & useMemo

Conclusion

React is a powerful library for building modern web applications. By mastering the fundamentals—components, state, props, and hooks—you can create dynamic and scalable applications.

Next Steps

Build a small project (e.g., a to-do app).
Explore advanced topics like Redux or Context API for state management.
Contribute to open-source React projects.

Happy coding! 🚀

FAQs for “A Beginner’s Guide to React: Getting Started”

1. What is React?

React is a JavaScript library developed by Facebook (Meta) for building user interfaces, particularly single-page applications (SPAs). It allows developers to create reusable UI components.

2. Why should I learn React?

React is in high demand, offers reusable components, improves performance with the Virtual DOM, and has strong community support. Companies like Facebook, Netflix, and Airbnb use it.

3. What are the prerequisites for learning React?

You should know:

HTML & CSS
JavaScript (ES6+)
Basic Node.js & npm/yarn

4. How do I set up a React project?

Use Create React App (CRA):

bash

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npx create-react-app my-app
cd my-app
npm start

5. What are React components?

Components are reusable UI elements. There are two types:

Functional Components (using hooks)
Class Components (older syntax)

6. What is JSX?

JSX is a syntax extension for JavaScript that allows writing HTML-like code inside JavaScript.

7. What are props in React?

Props (short for “properties”) allow passing data from parent to child components.

8. What is state in React?

State is used to manage dynamic data within a component. In functional components, use useState; in class components, use this.state.

9. How do I handle events in React?

Use camelCase syntax (e.g., onClick, onChange) and pass a function as a handler.

10. How do I conditionally render components?

Use JavaScript conditions like if, &&, or ternary operators inside JSX.

11. How do I render lists in React?

Use map() and assign a unique key prop to each list item for performance optimization.

12. How do I add routing in React?

Use React Router:

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npm install react-router-dom

Then define routes using <BrowserRouter>, <Route>, and <Link>.

13. How do I fetch data in React?

Use fetch or axios inside useEffect (for functional components) or lifecycle methods (for class components).

14. What are the best ways to style React components?

Inline styles
CSS Modules
Styled Components
Tailwind CSS

15. How do I deploy a React app?

Use platforms like:

Vercel
Netlify
GitHub Pages
Firebase Hosting

First, run:

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npm run build

Then upload the build folder.

16. What are some best practices in React?

Keep components small and reusable
Use functional components with hooks
Avoid direct state mutations
Use PropTypes or TypeScript for type safety
Optimize performance with React.memo and useMemo

17. What should I learn after React basics?

State management (Redux, Context API)
Server-side rendering (Next.js)
Advanced hooks (useReducer, useCallback)
API integration (GraphQL, REST)

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Redefining industries through custom product development.

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A Beginner’s Guide to React: Getting Started

Introduction to React

Why Learn React?

Prerequisites for Learning React

Setting Up Your First React Project

1. Install Node.js

2. Create a React App

3. Navigate to Your Project

4. Start the Development Server

Understanding React Project Structure

Core Concepts of React

1. Components

Example of a Functional Component

Example of a Class Component

2. JSX (JavaScript XML)

3. Props (Properties)

4. State

Using State in Functional Components (Hooks)

Using State in Class Components

5. Lifecycle Methods (Class Components) & useEffect (Functional Components)

Handling Events in React

Conditional Rendering

Lists and Keys

React Router for Navigation

Installation

Example Usage

Fetching Data in React

Styling in React

Deploying a React App

Best Practices for React Development

Conclusion

Next Steps

FAQs for “A Beginner’s Guide to React: Getting Started”

1. What is React?

2. Why should I learn React?

3. What are the prerequisites for learning React?

4. How do I set up a React project?

5. What are React components?

6. What is JSX?

7. What are props in React?

8. What is state in React?

9. How do I handle events in React?

10. How do I conditionally render components?

11. How do I render lists in React?

12. How do I add routing in React?

13. How do I fetch data in React?

14. What are the best ways to style React components?

15. How do I deploy a React app?

16. What are some best practices in React?

17. What should I learn after React basics?

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