The PowerPoint presentation titled "An Introduction to ReactJS" provides a beginner-friendly overview of ReactJS, a popular JavaScript library used for building user interfaces. This presentation aims to introduce ReactJS to individuals who may not have prior technical knowledge or experience with web development. The presentation begins with a brief introduction to ReactJS, explaining that it is a JavaScript library created by Facebook for building interactive and dynamic user interfaces. It highlights ReactJS's key features, such as component-based architecture and virtual DOM. Next, the presentation focuses on the benefits of using ReactJS. It explains that ReactJS enhances the user experience by enabling the creation of highly responsive and efficient web applications. It emphasizes React's ability to manage complex UI components and handle data updates seamlessly. To make the concept more relatable, the presentation provides real-world examples of popular websites and applications that use ReactJS. This helps the audience understand how ReactJS is implemented in real-world scenarios and its impact on user interface development. Furthermore, the presentation covers the basic concepts of ReactJS, such as components, props, and state. It explains that ReactJS follows a modular approach, where the UI is divided into reusable components, making it easier to manage and update the application. It also gives a high-level overview of how props and state are used to manage data flow within React components. Throughout the presentation, visual aids such as diagrams, screenshots, and simple illustrations are used to enhance understanding and engage the audience. The focus is on simplifying complex concepts and making them accessible to non-technical individuals. Finally, the presentation concludes by highlighting the vast community support and resources available for learning ReactJS. It encourages the audience to explore further and provides recommendations for online tutorials, documentation, and learning platforms. Overall, the "An Introduction to ReactJS" PowerPoint presentation aims to provide a non-technical audience with a basic understanding of ReactJS, its benefits, and its relevance in modern web development.

1. An Introduction to
ReactJS

2. What is React?
- React is a Javascript framework that focuses on declarative syntax
and virtualization of DOM.
- It is an open-source Javascript library, Developed by Meta in 2013.
- It provides a declarative and efficient way to create interactive UI
components.
- It allows building more reusable and maintainable UI components
with ease.

3. Why React?
Virtual DOM
- A Virtual DOM is a lightweight copy of the real DOM.
- Traditionally, only way to change content dynamically on
web was to manipulate the real DOM.
- React's virtual DOM allows for efficient updates and
selective rendering, resulting in faster and smoother
user experiences.

4. Why React?
- Component-based Architecture
- ReactJS follows a component-based architecture, where UIs are divided into
reusable components.
- Traditional web development often involves a mix of HTML, CSS, and
JavaScript, leading to tightly coupled code.
- React's component-based approach promotes modularity, reusability, and
easier maintenance of code.

5. Why React?
- Unidirectional Data Flow
- ReactJS enforces a unidirectional data flow, also known
as one-way binding.
- Traditional web development often involves two-way data binding,
where changes in one part of the application affect others,
making it harder to track and manage data changes.
- React's unidirectional data flow simplifies data management,
reducing the likelihood of bugs and making the application
easier to reason about.

6. Why React?
- State Management
- State management is a critical aspect of building complex
web applications.
- ReactJS provides several options for managing state
Efficiently within its ecosystem.
- Various ways of State Management:
- Local Component State
- useState
- Context API
- Redux

7. What is a React Component?
- ReactJS follows a component-based architecture, where UIs
are composed of reusable building blocks called components.
- A React component is a JavaScript function or class that
returns a JSX (JavaScript XML) representation of the UI.
- It encapsulates the UI logic and state, making it
reusable and modular.
- React supports two ways of declaring a component-
- Class Components
- Functional Components

8. Structure of React Component
- Props
- Props allow passing data from parent components to child components.
- Props are read-only and should not be modified within the component.
- State
- State represents the mutable data within a component.
- State is typically managed within class components using the this.state object and the
setState method.
- Functional components can also have state using React hooks like useState.
- Styling
- Styling can be applied to React components using CSS classes, inline styles, or CSS-in-JS
libraries.
- CSS classes can be added using the className attribute in JSX.
- Inline styles can be applied using the style attribute in JSX.

9. What is JSX?
- JSX (JavaScript XML) is a syntax extension for
JavaScript used in React.
- JSX allows you to write HTML-like code within JavaScript,
making it easier to create and manipulate the UI.
- JSX allows embedding JavaScript expressions within
curly braces {}.
- JSX needs to be compiled into plain JavaScript to be
understood by the browser.

10. Component Life Cycle
- React components have a life cycle consisting of different phases and methods that are
executed at specific times.
- The mounting phase is when a new component is
created and inserted into the DOM.
- The updating phase is when the component updates
or re-renders. This reaction is triggered when the
props are updated or when the state is updated.
- The last phase within a component's lifecycle is the
unmounting phase, when the component is removed
from the DOM.

11. Life Cycle Hooks
- componentDidMount()
- This hook is called after a component is mounted (rendered for the first time) in the DOM.
- componentDidUpdate(prevProps, prevState)
- This hook is called after a component is updated and re-rendered in response to changes in
props or state.
- componentWillUnmount()
- This hook is called just before a component is unmounted and removed from the DOM.
- shouldComponentUpdate(nextProps, nextState)
- This hook is called before a component is re-rendered and allows you to control if the re-
rendering should occur.

12. Running a React Application
- To run a React Application, we need to install
- NodeJS
- Node Package Manager (NPM)
- Install create-react-app
- npm install -g create-react-app
- Create React Application
- npx create-react-app my-app
- Run development server
- cd my-app
- npm start
- Build Project
- npm run build

13. Conclusion
- React is a powerful JavaScript library for building user interfaces.
- React's component-based architecture and efficient rendering make it a
popular choice for front-end development.
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