React

Question 1

What is in React 18?

Answer 1

• Root API
• Automatic batching
• Concurrent rendering (useTransition and useDeferredValue)
• Suspense feature
• New hooks
  
  • useId
  • useTransition
  • useDeferredValue

Question 2

What are the key features of React?

Answer 2

• Component-Based: React allows you to build encapsulated components that manage their state.
• Virtual DOM: React uses a virtual DOM to efficiently update the UI by only rendering the necessary components that have changed.
• JSX: JSX is a syntax extension that allows you to write HTML-like code within JavaScript, making it easier to define React components.
• One-Way Data Binding: React follows a unidirectional data flow, which means data flows from parent to child components to maintain a predictable state.

Question 3

What are React hooks?

Answer 3

React hooks are functions that let you use state and enable functional components to have state and lifecycle features previously available only in class components.

Question 4

What is Virtual DOM?

Answer 4

The Virtual DOM (VDOM) is an in-memory representation of Real DOM. The representation of a UI is kept in memory and synced with the “real” DOM. It’s a step that happens between the render function being called and the displaying of elements on the screen. This entire process is called reconciliation.

Question 5

What is Redux?

Answer 5

Redux is a state container for JavaScript applications, commonly used with libraries like React or Angular for managing application state in a more organized and predictable way.

Question 6

What are key concepts in Redux?

Answer 6

1. Single Source of Truth:
   
   • Redux stores the entire state of your application in a single immutable object tree (known as the “state” or “store”).
   • This single source of truth makes it easier to manage and debug application state.
2. State is Read-Only:
   
   • The state in Redux is immutable and cannot be changed directly.
   • To update the state, you dispatch actions that describe the change you want to make.
3. Changes are Made with Pure Functions:
   
   • Redux uses pure reducer functions to specify how the application’s state changes in response to actions.
   • Reducer functions take the previous state and an action as arguments and return the new state.
4. Unidirectional Data Flow:
   
   • Actions are dispatched to the Redux store, where they are processed by reducers to update the state.
   • Components can subscribe to changes in the state and re-render based on updated data.

Question 7

Why use Redux?

Answer 7

• Predictable State Management
• Single Source of Truth
• Unidirectional Data Flow
• Maintainability and Scalability
• Time Travel Debugging
• Integration with Middleware
• Ecosystem and Community Support

Question 8

What is Redux-Saga?

Answer 8

A middleware library for Redux that helps manage side effects (such as asynchronous tasks like data fetching and impure operations) in a Redux application