REACT JS — Greeting Component

    React has revolutionized the way we think about web applications with its efficient rendering and intuitive component-based architecture. If you’re new to React or looking to start a new project quickly, create-react-app is the perfect tool to get you up and running. This guide will walk you through creating a React application using create-react-app, dive into the folder structure, and explain the app execution workflow.

Getting Started with create-react-app

``create-react-app`` is a command-line tool that sets up a new React project with a good default configuration. It creates a project directory with all the necessary files, dependencies, and a local development server.

Prerequisites

• Node.js and npm installed on your computer. Verify by running node -v and npm -v in your terminal.
• Basic familiarity with terminal commands and JavaScript.

Creating Your React App

1. Open Your Terminal: Navigate to the directory where you want your project to live.
2. Run the Command: Execute npx create-react-app my-react-app, replacing my-react-app with your desired project name.
3. Navigate into Your Project: Once the installation is complete, move into your project directory by running cd ``my-react-app``.
4. Start the Development Server: Run npm start. This command will open your default browser to `http://localhost:3000`, where you can see your new React app running.

Congratulations! You’ve successfully created a React app. Now, let’s explore what `create-react-app` has set up for us.

Understanding the Folder Structure

                      When you first open your project in your favorite code editor, you’ll notice that create-react-app has generated a bunch of files and folders. Here’s a breakdown of the most important ones:

• node_modules/: Contains all the project’s npm dependencies.
• public/: Houses the index.html file and other assets like images. This is where your application gets served in the browser.
• src/: The heart of your React application. This directory contains your React component files, CSS, and JavaScript.
  • App.js: The main React component that serves as the entry point for your application.
  • index.js: The JavaScript entry point, responsible for rendering your App component to the DOM.
  • App.css: The stylesheet for your App component.
  • index.css: Global styles for your application.
• package.json: Lists the project’s dependencies and contains scripts for running, building, and testing your app.
• .gitignore: Specifies intentionally untracked files to ignore.

Workflow of App Execution

The execution of a React app created with create-react-app follows a specific flow:

1. Starting the Development Server: When you run `npm start`, `create-react-app` starts a development server that compiles your React code into JavaScript the browser can understand, using Babel and webpack under the hood.

2. Serving the App: The server serves the `index.html ` file from the `public` directory. However, this HTML file is merely a container. The real magic happens in the `src/index.js` file.

3. Rendering the App: The index.js file imports the App component from App.js and uses ReactDOM.render to render it inside the <div id="root"></div> element in index.html.

4. Component Hierarchy: Your entire app’s UI is built as a hierarchy of components starting from the App component. Components can be classes or functions that return HTML elements defining parts of your UI.

5. Hot Reloading: Any changes you make to your component files are automatically recompiled and the browser is refreshed, thanks to the development server’s hot reloading feature.