What is React and How to Use It? (A Beginner’s Guide)

In this article, I will break down what React is, why it is so popular, and how you can get started using it for your own web development projects.

What is React?

React is a JavaScript library used for building user interfaces (UI). A UI is the part of a website or application that users interact with. It is everything from the buttons you click to the text you read and the images you view.

In the past, creating dynamic UIs for websites was a challenging task. But React makes it easier and faster.

React was developed by Facebook in 2011 and released as an open-source project in 2013. Since then, it has grown to become one of the most popular tools for building web applications, used by companies like Facebook, Instagram, Netflix, and Airbnb.

So, when someone says they are using React, it typically means they are using this library to build the interface that you see and interact with on websites and apps.

Why is React so Popular?

There are a few reasons why React has become so widely adopted by developers. Let us take a look at them:

• Component-Based Structure
  React uses a component-based approach to building user interfaces. This means that rather than building everything from scratch, developers can create small, reusable pieces of code called components. A component can be a button, a form, or even an entire webpage. This modular structure helps developers work more efficiently and maintain their code more easily.
• Fast and Efficient
  React uses a concept called the Virtual DOM (Document Object Model). Instead of updating the entire webpage every time something changes (like when you click a button), React updates only the part of the page that needs to change. This makes web applications built with React faster and more responsive.
• Easy to Learn
  React has a relatively low learning curve compared to other JavaScript frameworks. It’s flexible and straightforward, allowing developers to get up and running quickly. The React documentation is also beginner-friendly, making it easier for newcomers to learn the library.
• Huge Community and Ecosystem
  React has a large and active community of developers who contribute to its growth. There are countless tutorials, libraries, and tools available that make it easier to build with React. If you run into an issue, chances are someone else has faced the same problem, and you can find a solution online.
• Backed by Facebook
  Since React was developed by Facebook, it is continuously improved and maintained by them. This gives React stability and ensures that it remains up-to-date with the latest web development trends.

How Does React Work?

To understand how React works, it’s important to grasp a few key concepts: components, JSX, and state.

1. Components

As we mentioned earlier, React applications are built using components. A component is a small, self-contained piece of UI that can be reused throughout the application. For example, a “Login Button” component could be used on the homepage, the login page, and any other page that requires a login button.

Components in React can either be functional components or class components, but with the introduction of React Hooks, functional components have become the preferred method.

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

In this example, Welcome is a functional component that accepts props (short for properties). The component then returns an HTML-like element, in this case, an <h1> tag with a personalized greeting.

2. JSX

JSX stands for JavaScript XML. It is a syntax extension for JavaScript that allows you to write HTML-like code within your JavaScript files. While you don’t have to use JSX to build a React app, it makes writing components much easier.

  function App() {
    return (
      <div>
        <h1>Welcome to React!</h1>
        <p>This is an example of JSX syntax.</p>
      </div>
    );
  }
  

Notice how the syntax looks very similar to HTML, but it’s actually JavaScript code. React will automatically convert the JSX code into actual HTML elements when the app is rendered in the browser.

3. State

In React, state refers to the data that a component can use to keep track of changes. This is useful when building interactive applications where the content of a page changes based on user interaction, like submitting a form or clicking a button.

  import React, { useState } from 'react';

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

    return (
      <div>
        <p>You clicked {count} times</p>
        <button onClick={() => setCount(count + 1)}>Click me</button>
      </div>
    );
  }
  

In this example, useState is a React Hook that creates a piece of state for the count variable. The state is updated whenever the user clicks the button, causing the UI to re-render with the new value.

How to Use React?

Now that you have a basic understanding of what React is and how it works, let me go over how you can start using it in your own projects.

1. Setting Up Your Environment

To use React, you will need a few things:

• Node.js and npm (Node Package Manager): React requires Node.js to run JavaScript code outside the browser. npm is a package manager that lets you install libraries like React.
• Code Editor: You can use any code editor, but Visual Studio Code is a popular choice for React development.
• React Development Tools: These are browser extensions that make it easier to debug and inspect React applications.

Once you have those tools set up, you can create a new React project using Create React App, which is an official React tool that helps you set up a new project quickly.

  npx create-react-app my-app
  

This command will create a new folder called my-app with all the necessary files and dependencies for a React project. Once the process is complete, you can navigate into the my-app folder and start the development server:

  cd my-app
  npm start
  

Your app will now be running locally in your browser at http://localhost:3000/.

2. Building a Simple React App

Let’s start by building a very basic React app that displays a greeting.

1. Inside your src folder, open the App.js file. This file contains the main component for your app.
2. Replace the contents of the App.js file with the following code:

  import React from 'react';

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

  export default App;
  

3. Save the file. Your browser should automatically refresh, and you’ll see the message “Hello, React!” displayed on the page.

Congratulations! You’ve just created your first React app.

Tips for Learning React

If you are new to React, here are some tips to help you along the way:

• Start with the Official Documentation
  React’s official documentation is well-written and beginner-friendly. It’s a great resource to help you understand React’s core concepts.
• Practice, Practice, Practice
  The best way to learn React (or any programming language) is to build projects. Start with small projects and gradually take on bigger challenges.
• Join the Community
  There are many forums, groups, and online communities where React developers share knowledge and help each other. Consider joining forums like StackOverflow or Reddit to ask questions and share your progress.
• Don’t Get Overwhelmed
  React has a lot of features, and it can be overwhelming at first. Take it one step at a time, and don’t be afraid to ask for help.