Complete React.js course in Telugu by Vamsi Bhavani in just 45 minutes

Welcome to this detailed tutorial on React.js in Telugu. In this course, we will cover everything you need to know about React.js, from the basics to advanced topics. This course is designed for beginners and experienced developers alike.

Before we start with the tutorial, let me introduce myself. I am Vamsi Bhavani, a software developer and React.js enthusiast. I have been working with React.js for several years and I am excited to share my knowledge with you in this course.

Let’s begin with an introduction to React.js. React.js is an open-source JavaScript library that is used for building user interfaces. It was created by Facebook and has gained popularity among developers due to its simplicity and flexibility.

React.js allows developers to build interactive user interfaces by creating components that can be reused and managed independently. This makes it easier to maintain code and scale applications as they grow.

Now, let’s dive into the main topics we will cover in this course:

1. Introduction to React.js
2. Setting up a React development environment
3. Creating and using components
4. Handling events and state in React
5. Working with props and passing data between components
6. Rendering lists and iterating through data
7. Conditional rendering in React
8. Forms and form handling in React
9. Lifecycle methods in React
10. Routing in React
11. HTTP requests in React
12. State management in React using Redux
13. Testing React applications
14. Deploying a React application

By the end of this course, you will have a solid understanding of React.js and be able to build your own applications using this powerful library.

Now, let’s start the tutorial.

Step 1: Setting up a React development environment

To get started with React.js, you need to have Node.js installed on your computer. Node.js is a JavaScript runtime that allows you to run JavaScript code outside of a web browser.

You can download and install Node.js from the official website: https://nodejs.org

Once you have Node.js installed, you can use the Node Package Manager (npm) to install create-react-app, a tool that helps you set up a new React project quickly.

To install create-react-app, open a terminal window and run the following command:

npm install -g create-react-app

This command will install create-react-app globally on your computer, allowing you to use it from any directory.

Now, you can create a new React project by running the following command:

create-react-app my-react-app

Replace "my-react-app" with the name of your project. This command will create a new directory with all the necessary files and folders for a React project.

To start the development server, navigate to your project directory and run the following command:

cd my-react-app
npm start

This will start the development server and open your React application in a web browser. You should see a default React logo and message on the screen.

Congratulations! You have successfully set up a React development environment and created your first React project.

In the next steps, we will start learning about React components and how to create and use them in our applications.

Step 2: Creating and using components

In React.js, components are the building blocks of a user interface. A component can be thought of as a small, reusable piece of code that represents a part of a user interface, such as a button, input field, or navigation menu.

To create a new component in React, you can use the class-based or functional component syntax. Here’s an example of a simple functional component:

import React from 'react';

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

export default Hello;

In this example, we define a functional component called Hello that renders a heading element with the text "Hello, world!". We then export the component so that it can be used in other parts of our application.

To use the Hello component in another file, you can import it like this:

import React from 'react';
import Hello from './Hello';

function App() {
  return (
    <div>
      <Hello />
    </div>
  );
}

export default App;

In this example, we import the Hello component from the file where it is defined and use it inside the App component. When you run your React application, you should see the "Hello, world!" heading displayed on the screen.

Now that you have learned how to create and use components in React, let’s move on to the next step: handling events and state in React.

Step 3: Handling events and state in React

In React.js, state is used to store and manage data that can change over time, such as user input or application state. State is used to update the user interface and respond to user interactions.

To add state to a React component, you can use the useState hook, which is a built-in React hook that allows you to add state to functional components. Here’s an example of how to add state to a functional component:

import React, { useState } from 'react';

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

  const increment = () => {
    setCount(count + 1);
  };

  return (
    <div>
      <p>{count}</p>
      <button onClick={increment}>Increment</button>
    </div>
  );
}

export default Counter;

In this example, we define a functional component called Counter that uses the useState hook to create a count state variable with an initial value of 0. We also define an increment function that updates the count state when the button is clicked.

To use the Counter component in another file, you can import it like this:

import React from 'react';
import Counter from './Counter';

function App() {
  return (
    <div>
      <Counter />
    </div>
  );
}

export default App;

When you run your React application, you should see a counter with an "Increment" button that increases the count value each time it is clicked.

Now that you have learned how to handle events and state in React, let’s move on to the next step: working with props and passing data between components.

Step 4: Working with props and passing data between components

In React.js, props are used to pass data from a parent component to a child component. Props are read-only and cannot be modified by the child component.

To pass props to a child component, you can add attributes to the component tag when rendering it in the parent component. Here’s an example of how to pass props to a child component:

import React from 'react';

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

export default Greet;

In this example, we define a functional component called Greet that takes a name prop and renders a heading element with a personalized greeting. To pass the name prop to the Greet component, you can use it like this:

import React from 'react';
import Greet from './Greet';

function App() {
  return (
    <div>
      <Greet name="Alice" />
      <Greet name="Bob" />
    </div>
  );
}

export default App;

In this example, we render two instances of the Greet component with different name props. When you run your React application, you should see two personalized greetings displayed on the screen.

Now that you have learned how to work with props and pass data between components, let’s move on to the next step: rendering lists and iterating through data.

Step 5: Rendering lists and iterating through data

In React.js, you can render lists of data by using the map function to iterate through an array of items and render them as components. This allows you to render dynamic content based on the data in the list.

Here’s an example of how to render a list of items in React:

import React from 'react';

function App() {
  const items = ['Apple', 'Banana', 'Cherry'];

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

export default App;

In this example, we define an array of items and use the map function to iterate through the array and render a list item for each item. We also add a key prop to each list item to help React identify each item in the list.

When you run your React application, you should see a list of items displayed on the screen.

Now that you have learned how to render lists and iterate through data in React, let’s move on to the next step: conditional rendering in React.

Step 6: Conditional rendering in React

In React.js, you can use conditional statements, such as if-else statements and ternary operators, to render different content based on certain conditions. This allows you to show or hide elements dynamically in your user interface.

Here’s an example of how to use conditional rendering in React:

import React from 'react';

function App() {
  const isLoggedIn = true;

  return (
    <div>
      {isLoggedIn ? <p>Welcome, user!</p> : <p>Please log in</p>}
    </div>
  );
}

export default App;

In this example, we define a isLoggedIn variable that determines whether the user is logged in. We use a ternary operator to conditionally render different messages based on the value of isLoggedIn.

When you run your React application, you should see the appropriate message displayed on the screen based on the value of isLoggedIn.

Now that you have learned how to use conditional rendering in React, let’s move on to the next step: forms and form handling in React.

Step 7: Forms and form handling in React

In React.js, you can create forms to collect user input and handle form submissions using event handlers. Form elements such as input fields and buttons can be controlled by React state to update the user interface dynamically.

Here’s an example of how to create a simple form in React:

import React, { useState } from 'react';

function Form() {
  const [name, setName] = useState('');

  const handleChange = event => {
    setName(event.target.value);
  };

  const handleSubmit = event => {
    event.preventDefault();
    alert(`Hello, ${name}!`);
  };

  return (
    <form onSubmit={handleSubmit}>
      <input type="text" value={name} onChange={handleChange} />
      <button type="submit">Submit</button>
    </form>
  );
}

export default Form;

In this example, we define a form with an input field and a submit button. We use the useState hook to create a name state variable that stores the value of the input field. We also define event handlers for the input field and form submission.

When you run your React application and enter your name in the input field and submit the form, you should see an alert message with your name displayed on the screen.

Now that you have learned how to create forms and handle form submissions in React, let’s move on to the next step: lifecycle methods in React.

Step 8: Lifecycle methods in React

In React.js, components have lifecycle methods that allow you to run code at certain points in the life of a component, such as when it is mounted, updated, or unmounted. Using lifecycle methods can help you manage state, handle side effects, and optimize performance in your React applications.

Here’s an example of how to use the useEffect hook, which is a built-in React hook that allows you to perform side effects in functional components:

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

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

  useEffect(() => {
    document.title = `Count: ${count}`;
  }, [count]);

  const increment = () => {
    setCount(count + 1);
  };

  return (
    <div>
      <p>{count}</p>
      <button onClick={increment}>Increment</button>
    </div>
  );
}

export default App;

In this example, we use the useEffect hook to update the document title with the current count value whenever the count state changes. We also specify count as a dependency for the effect so that it only runs when count changes.

When you run your React application and click the "Increment" button, you should see the count value displayed in the document title.

Now that you have learned how to use lifecycle methods in React, let’s move on to the next step: routing in React.

Step 9: Routing in React

In React.js, routing allows you to navigate between different pages or views in a single-page application without reloading the entire page. You can use a routing library, such as React Router, to set up and manage routes in your React application.

To get started with routing in React, you can install React Router by running the following command:

npm install react-router-dom

Once React Router is installed, you can set up routes in your React application by using the Router, Route, and Link components from the react-router-dom package.

Here’s an example of how to set up routes in React using React Router:

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

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

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

function App() {
  return (
    <Router>
      <nav>
        <ul>
          <li>
            <Link to="/">Home</Link>
          </li>
          <li>
            <Link to="/about">About</Link>
          </li>
        </ul>
      </nav>
      <Route path="/" exact component={Home} />
      <Route path="/about" component={About} />
    </Router>
  );
}

export default App;

In this example, we define two functional components, Home and About, that represent different views in our application. We set up routes for the Home and About components using the Route component and specify the paths for each route.

When you run your React application and navigate to the different routes using the links in the navigation menu, you should see the corresponding views displayed on the screen.

Now that you have learned how to set up routing in React using React Router, let’s move on to the next step: HTTP requests in React.

Step 10: HTTP requests in React

In React.js, you can make HTTP requests to external APIs to fetch data and update the user interface dynamically. You can use libraries such as Axios or the built-in fetch API to send GET, POST, PUT, and DELETE requests and handle responses in your React application.

To make HTTP requests in React, you can install the Axios library by running the following command:

npm install axios

Once Axios is installed, you can use it to fetch data from an external API in your React application. Here’s an example of how to make a GET request using Axios:

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

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

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

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

export default App;

In this example, we use the useEffect hook to fetch data from the JSONPlaceholder API and store it in the data state variable. We then render a list of posts by mapping over the data array and displaying the title of each post.

When you run your React application, you should see a list of post titles displayed on the screen fetched from the JSONPlaceholder API.

Now that you have learned how to make HTTP requests in React using Axios, let’s move on to the next step: state management in React using Redux.

Step 11: State management in React using Redux

In React.js, managing state can become complex as your application grows in size and complexity. Redux is a popular state management library for React that allows you to manage and update global state in a predictable way.

To get started with Redux in React, you can install the Redux and React-Redux libraries by running the following commands:

npm install redux
npm install react-redux

Once Redux and React-Redux are installed, you can set up a Redux store and create reducers and actions to manage and update state in your React application.

Here’s an example of how to set up Redux in React:

// store.js

import { createStore } from 'redux';
import rootReducer from './reducers';

const store = createStore(rootReducer);

export default store;

// reducers.js

import { combineReducers } from 'redux';

const rootReducer = combineReducers({
  // Add your reducers here
});

export default rootReducer;

// actions.js

export const increment = () => ({
  type: 'INCREMENT'
});

// App.js

import React from 'react';
import { useSelector, useDispatch } from 'react-redux';
import { increment } from './actions';

function App() {
  const count = useSelector(state => state.count);
  const dispatch = useDispatch();

  return (
    <div>
      <p>{count}</p>
      <button onClick={() => dispatch(increment())}>Increment</button>
    </div>
  );
}

export default App;

In this example, we define a Redux store, combine reducers, create an action to increment the count value, and use useSelector and useDispatch hooks from React-Redux to access and update state in our React component.

When you run your React application and click the "Increment" button, you should see the count value increase in the user interface managed by Redux.

Now that you have learned how to manage state in React using Redux, let’s move on to the next step: testing React applications.

Step 12: Testing React applications

In React.js, testing is an important part of the development process to ensure that your application works as expected and handles edge cases properly. You can use testing libraries such as Jest and React Testing Library to write unit tests and integration tests for your React components.

To get started with testing in React, you can install Jest and React Testing Library by running the following commands:

npm install --save-dev jest @testing-library/react @testing-library/jest-dom

Once Jest and React Testing Library are installed, you can write tests for your React components using the test function from Jest and the render function from React Testing Library.

Here’s an example of how to write a simple test for a React component:

// App.test.js

import React from 'react';
import { render, screen } from '@testing-library/react';
import App from './App';

test('renders the app component', () => {
  render(<App />);
  const headingElement = screen.getByText('Hello, world!');
  expect(headingElement).toBeInTheDocument();
});

In this example, we write a test that checks if the App component renders a heading element with the text "Hello, world!". We use the getByText function from React Testing Library and the toBeInTheDocument matcher from Jest to make assertions about the content of the rendered component.

When you run your test using the Jest test runner, you should see the test pass if the component renders the expected content.

Now that you have learned how to write tests for React components using Jest and