React.js Complete Beginner Tutorial: Learn React from Scratch

Welcome to React.js

React.js is a popular JavaScript library used for building user interfaces. It's maintained by Facebook and a community of developers. In this tutorial, we'll take you through the basics of React.js and help you get started with building your own applications.

Setting Up Your Environment

To start using React.js, you'll need to set up your environment. This includes installing Node.js, a code editor, and a package manager like npm or yarn. Once you have these tools installed, you can create a new React project using the create-react-app command.

Basic Concepts in React.js

Here are some key concepts to understand when getting started with React.js:

• Components: These are the building blocks of your application. You can think of them as functions that return JSX (a syntax extension for JavaScript).
• JSX: This is a syntax extension for JavaScript that allows you to write HTML-like code in your JavaScript files.
• State: This refers to the data that changes in your application. In React.js, state is used to store data that can change over time.
• Props: These are short for properties and are used to pass data from a parent component to a child component.

Building Your First React Component

Let's build a simple React component to get started. Create a new file called Hello.js and add the following code:

         import React from 'react';
         
         function Hello() {
            return 
Hello World!
;
         }
         
         export default Hello;
      

This component returns an h1 element with the text 'Hello World!'. You can then import and use this component in your main App.js file.

Handling State and Props

Let's update our Hello component to handle state and props. We'll add a button that increments a counter when clicked.

         import React, { useState } from 'react';
         
         function Hello(props) {
            const [count, setCount] = useState(0);
            
            return (
               

                  
Hello {props.name}!
                  
Count: {count}
                  
               
            );
         }
         
         export default Hello;
      

In this example, we're using the useState hook to store the count in state. We're also passing a name prop to the component and displaying it in the h1 element.

Conclusion

In this tutorial, we've covered the basics of React.js and built a simple component to get you started. We've also explored how to handle state and props in your components.

Frequently Asked Questions

Here are some frequently asked questions about React.js:

• What is React.js? React.js is a JavaScript library used for building user interfaces.
• Do I need to know JavaScript to use React.js? Yes, you should have a basic understanding of JavaScript and HTML/CSS to use React.js.
• How do I get started with React.js? You can get started with React.js by installing Node.js and a code editor, then creating a new React project using the create-react-app command.
• What is the difference between React.js and Angular.js? React.js and Angular.js are both JavaScript libraries used for building user interfaces, but they have different architectures and use cases.
• Is React.js suitable for large-scale applications? Yes, React.js is suitable for large-scale applications and is used by many big companies like Facebook and Instagram.

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Published: 2026-05-27