Introduction to ReactJS

Introduction to ReactJS

• React is a JavaScript library for building user interfaces (UIs).
• It's sometimes referred to as a frontend JavaScript framework.
• Developed by Facebook.
• Used to create reusable, nestable UI components.
• Components are fundamental units for building UIs, encompassing everything from simple buttons to complex applications.
• React offers tools for creating, customizing, and conditionally displaying components.

What is React?

• A JavaScript library for creating user interfaces (UIs).
• Provides a structure for building interactive user interfaces.
• Encourages modular architecture, allowing developers to break down a UI into smaller, more manageable components.
• Aims to create fast and responsive web applications, primarily front-end focused.

React Describing UI

• React is used for presenting UI elements on the screen.
• It builds UI components from smaller units, such as buttons, text, and images.
• UI components can be combined, reused, and nested to create complete user experiences.
• Components break down complex interfaces into simpler units.

ReactJS

• JavaScript framework for building web applications.
• Fast response due to its in-browser execution.
• Model-View-Controller (MVC) pattern is employed to structure the application.
• Components are used to describe the UI elements and how they interact dynamically.
• Promotes efficient programming on large and single-page application projects.
• Features reusability, modularity, testing, and other standard development practices.

How does React Work?

• React uses a virtual DOM (Document Object Model).
• A virtual representation of the actual DOM is created and updated in memory.
• Changes are made to the virtual DOM before applying them to the real DOM.
• React updates only the parts of the DOM that need to change, resulting in greater speed and efficiency.

ReactJS History

• Current version is v18.0.0 (April 2022).
• Initial public release was v0.3.0 in July 2013.
• Initially used in 2011 for Facebook's Newsfeed development.
• Created by Facebook software engineer, Jordan Walke.
• create-react-app is a tool to create projects, with the latest version being v5.0.1 (April 2022).
• This tool includes essential tools like webpack, Babel, and ESLint.

React Getting Started

• Use npm (Node Package Manager) included with Node.js.
• Direct HTML integration to experiment with React concepts.

Setting up a React Environment

• Requires npx and Node.js installation.
• create-react-app command is used to build new application projects.
• Uninstall the globally installed version of create-react-app if previously installed.

Run the React Application

• Navigate to the project directory using cd.
• Launch the application using the npm start command.
• Application should open in a new browser window at localhost:3000.

ReactJS Web Application Page

• React and ReactDOM components are imported.
• Hello function that returns the structure for a "Hello World" message.
• A container element is obtained from document.getElementById.
• The rendered Hello component is displayed in the root container.

React JSX

• JSX (JavaScript XML) is a syntax extension for JavaScript to work with HTML elements.
• Write HTML-like code directly within JavaScript.
• Makes writing HTML within React significantly easier.

Example 1 with JSX

• Example code showing basic JSX usage.

Example 2 Without JSX

• Using React's createElement method for a more direct approach to HTML structures within React using JavaScript.

Homework

• Complete provided tutorials.
• Watch YouTube tutorial videos.
• Consult ChatGPT for additional clarification.

This quiz covers the fundamentals of ReactJS, a popular JavaScript library for building user interfaces. It highlights the modular architecture of React, its component-based design, and its use for creating interactive and responsive front-end applications.