React introduction

React is a popular JavaScript library used for building web applications. It is often used in conjunction with other technologies such as Redux,TypeScript, and Node.js to create full-stack web applications. In this article, we’ll introduce the basics of using React to build web applications.

Getting Started with React

To use React, you will need to install a few tools on your computer. The first step is to install Node.js, which comes with the Node Package Manager or NPM. NPM is a package manager that installs and updates Node.js packages. Once you have Node.js and NPM installed, you can create a new React application using a tool called Create React App.

Create React App is a command-line tool that generates a new React application with a basic file structure and initial configuration. To create a new React application, run the following command in your terminal:
npx create-react-app my-app
This command creates a new directory called my-app and installs all the necessary dependencies for a React application. Once the installation is complete, you can start the development server by navigating to the my-app directory and running the following command:
cd my-app
npm start
This command starts the development server and opens a new tab in your web browser with the React app running. You should see a default React page that says “Welcome to React!” Creating a New Component

A component is a reusable building block of a React application. Components can be simple or complex, and they can contain other components. To create a new component, you can create a new file in the src/ directory with a .js or .jsx extension.
For example, let’s create a new component called “HelloWorld” that displays a message. Here’s the code for the component:

import React from 'react';
function HelloWorld() 
  {
   return (
       <div className="hello-world">
           <h1>Hello, world!</h1>
           <p>Welcome to my React app.</p>
       </div> 
      );
  }
 export default HelloWorld;

In this code, we use the React library to define a new component called “HelloWorld”. The component returns some JSX code that displays a heading and a paragraph.

Using a Component in Your App

Once you’ve created a component, you can use it in your app by importing it in another component. In the App.js file in our React app, we can use the “HelloWorld” component we just created like this:

import React from 'react';
import './App.css';
import HelloWorld from './HelloWorld';
function App() {
    return (<div className="App"><HelloWorld /></div>);
export default App;

In this code, we import the “HelloWorld” component and use it in the “App” component. When we run the app, we will see the message “Hello, world!” displayed on the screen.

Conclusion

In this article, we’ve introduced the basics of using React to build web applications. We’ve covered how to install the necessary tools, create a new React app, create a new component, and use a component in your app. With these basics, you can start building your own React applications and explore more advanced topics like Redux and TypeScript.