What is Reactjs and What are the key features of React – React Basics Interview Questions

React is a JavaScript library for building user interfaces or frontend, particularly for web applications. Developed by Facebook, React provides a declarative and component-based approach to building UI/Interface. It allows developers to create reusable UI components that manage their own state, making it easier to build complex user interfaces.

Key features of React include:

1. Virtual DOM

   React uses a virtual representation of the DOM (Document Object Model) to efficiently update the actual DOM when changes occur. This helps improve performance by minimizing the number of manipulations needed to update the user interface.

2. Declarative

   React allows developers to describe how the UI should look at any given point in time, and React takes care of efficiently updating and rendering the components when the underlying data changes. This declarative approach simplifies the process of building complex user interfaces by abstracting away the manual DOM manipulation

3. Component-Based Architecture

   React encourages the creation of reusable UI components. Each component encapsulates its own logic and state, making it easier to manage and maintain complex UIs.

4. JSX (JavaScript XML)

   React utilizes JSX, a syntax extension that allows developers to write HTML-like code within JavaScript. JSX makes it easier to describe UI components and their structure, blending HTML and JavaScript seamlessly.

5. Unidirectional Data Flow

   React follows a unidirectional data flow, where data flows downward from parent components to child components. This helps maintain a clear and predictable data flow within the application, which is crucial for managing state and updating the UI.

6. React Hooks

   Introduced in React 16.8, hooks are functions that allow developers to use state and other React features in functional components, which were previously only available in class components. Hooks provide a more concise and flexible way to manage state and side effects in React applications.

7. React Router

   React Router is a popular library for adding routing capabilities to React applications. It allows developers to define different routes within their application and render different components based on the URL, enabling the creation of single-page applications with multiple views.

Now days React has become widely adopted in the web development community due to its performance, flexibility, and developer-friendly features. It is often used in conjunction with other libraries and frameworks, such as Redux for state management and Next.js for server-side rendering.