Preeminent React JS Interview Inquiries and Responses: Essential Knowledge for Success

Preeminent React JS Interview Inquiries and Responses: Essential Knowledge for Success

prep for that React JS interview? Here's a list of common questions you might encounter, along with some insights to help you ace it:

1. What is React JS and why should you use it?

React is a JavaScript library developed by Facebook for building user interfaces. It allows developers to create reusable components, manage state efficiently, and renders components efficiently by using a VirtualDOM. Using React can make your UI more responsive, easier to test, and enable a smoother development experience.

2. Define Redux and its main components

Redux is an open-source library primarily used for managing application state, especially in combination with React. The three main components of Redux are:

1. Store - A single, central store that holds the entire state of your application.
2. Actions - Dispatched by components to specific reducers to update the state.
3. Reducers - Pure functions that handle incoming actions and return a new version of the state.

3. What is JSX, and what are its benefits?

JSX (JavaScript XML) is a syntax extension for JavaScript, allowing you to write HTML-like code inside JavaScript files. It gets compiled to React elements, making the application more robust and extendable. Some benefits of using JSX include a clearer API, increased productivity, and better readability of your code.

4. Explain the concept of the Virtual DOM and its advantages

The Virtual DOM is a lightweight representation of the actual DOM, used by React to make rendering more efficient. React compares the differences between the virtual DOM and the actual DOM, then only updates the necessary elements, preventing unnecessary re-renders and improving overall performance. Some benefits of using the Virtual DOM include faster rendering, consistent UI across different platforms, and reduced memory consumption.

5. List the main features of React

The key features of React include:

• Component-based architecture
• One-way data flow
• Declarative UI
• Virtual DOM
• Reusable components
• Easy to learn

6. What are the predefined prop types in React, and explain syntax examples

Prop types are used to ensure that a component is receiving the correct data type for the props it expects. Some basic prop types include:

• string:
• number:
• boolean:
• function:
• array:

Here's an example of using prop types:

7. Differences between React and React Native

React is a JavaScript library for building user interfaces for web applications, while React Native extends React to mobile platforms, allowing developers to build cross-platform native apps using the same component-based architecture as React.

8. What are the main types of React components?

In React, you have six primary types of components:

1. Functional components
2. Class components
3. Higher-order components
4. Dumb components
5. Smart components
6. Presentational components (for rendering UI) and container components (for handling data and state)

Some of these concepts might require more context to fully understand, but this list will help you identify the different kinds of components in React.

9. Describe the difference between states and props

• State: The data that React components manage internally. It can be mutated using the function and causes the component to re-render when it changes.
• Props: The data passed down from parent components to child components. Props cannot be mutated by child components and should always be treated as immutable values.

10. Why use Redux in a React application?

Redux improves the structure and organization of React applications, especially for managing complex state and data flows. It provides an easier way to manage shared state among multiple components, making the code easier to test, read, and maintain.

11. Explain the workings of Jest and dispatcher

• Jest: A JavaScript testing framework for testing React applications. It allows developers to write, run, and debug tests to ensure their code works as intended.
• Dispatcher: A pattern for updating application state by dispatching actions and managing the application's data flow.

12. Why is React important in the FrontEnd ecosystem?

React's component-based architecture, declarative UI, and VirtualDOM make it an essential tool for modern FrontEnd development. Its power, flexibility, and ease of use have revolutionized FrontEnd development and have become a cornerstone of web development.

1. I'm not just familiar with React JS, but I've also delved into other tech stacks like Java and Spring Framework for back-end programming.
2. In addition to Redux and React, I've worked with various technology frameworks and libraries for efficient coding and programming.
3. I appreciate the importance of React JS for web development, but I'm also very interested in exploring the benefits of JSX in JavaScript programming for better code readability and productivity.

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