QUIZ ON : react - MISCELLANEOUS

MISCELLANEOUS

00:00:00

Question No# : 01 out of 50

What is the purpose of React's "setState" method when called with a function as an argument?

A. It is used to define the initial state of a component

B. It is used to handle user interactions in a component

C. It is used to update the state of a component based on the previous state

D. It is used to render the component's UI

Question No# : 02 out of 50

What is the lifecycle method used for initializing state and binding event handlers in React?

A. componentDidMount

B. componentDidUpdate

C. componentWillMount

D. constructor

Question No# : 03 out of 50

What is the purpose of the "useEffect" hook in React?

A. To handle form validation in React components

B. To manage the lifecycle of functional components

C. To create custom hooks for reusable logic

D. To handle asynchronous operations in React components

Question No# : 04 out of 50

What is the purpose of the React Developer Tools extension?

A. It allows developers to inspect the component hierarchy and state in a React application

B. It provides a code editor specifically designed for writing React components

C. It enables real-time collaboration among multiple developers working on a React project

D. It automatically generates documentation for React components

Question No# : 05 out of 50

What is the default port where web pack-server runs?

A. 8080

B. 6060

C. 3000

D. 3030

Question No# : 06 out of 50

What is the purpose of React's "key" prop when rendering a list of elements?

A. It determines the order in which the list items are rendered

B. It ensures unique styling for each list item

C. It improves the performance of rendering the list

D. It helps React identify which items have changed, been added, or been removed

Question No# : 07 out of 50

Why is the usage of set State?

A. Access the previous state before the set State operation

B. Replace the state completely instead of the default merge action

C. Invoke code after the set State operation is done

D. None

Question No# : 08 out of 50

What is the concept of React portals?

A. It is a way to create reusable UI components in React

B. It is a mechanism to optimize rendering performance in React

C. It is a way to render React components outside of their parent component's DOM hierarchy

D. None of the above

Question No# : 09 out of 50

What helps react for keeping their data unidirectional.?

A. JSX

B. Props

C. Flux

D. DOM

Question No# : 10 out of 50

What is the purpose of React's "createContext" function?

A. It is used to create custom hooks in React

B. It is used to define the structure and layout of a React component

C. It is used to create a context object for sharing data across components

D. It is used to handle asynchronous operations and data fetching in React components

Question No# : 11 out of 50

How do you handle passing through the component tree without having to pass props down manually at every level?

A. React Send

B. React Pinpoint

C. React Router

D. React Context

Question No# : 12 out of 50

What is the purpose of the "React.memo" function in React?

A. It is used to memoize function components for performance optimization

B. It is used to create custom hooks in React

C. It is used to manage state in class components

D. None of the above

Question No# : 13 out of 50

In react, the key should be?

A. Unique among his siblings only

B. Unique in the DOM

C. Does not requires to be unique

D. all of the above

Question No# : 14 out of 50

What is the concept of "code splitting" in React?

A. It is a technique to divide code into smaller modules for better performance and optimization

B. It is a way to write cleaner and more maintainable code in React applications

C. It is a technique to improve the rendering performance of React components

D. None of the above

Question No# : 15 out of 50

What is the purpose of the "render" method in React?

A. To define the initial state of a component

B. To render the component's UI based on its current state and props

C. To handle user interactions and update the component's state

D. To define the lifecycle methods of a component

Question No# : 16 out of 50

What is the purpose of React hooks like "useMemo" and "useCallback"?

A. To optimize the performance of functional components by memoizing values and functions

B. To manage the state of functional components

C. To handle side effects in functional components

D. None of the above

Question No# : 17 out of 50

Which of the following is not a valid hook in React?

A. useState

B. useEffect

C. useData

D. useContext

Question No# : 18 out of 50

What is the significance of React's "virtual DOM"?

A. It is a way to optimize rendering performance in React applications

B. It is a mechanism to handle errors and fallback UI in React applications

C. It is a technique to render React components outside of their parent component's DOM hierarchy

D. It is a representation of the actual DOM in memory, allowing efficient updates and rendering

Question No# : 19 out of 50

What is the purpose of React's "useCallback" hook?

A. It is used to create reusable custom hooks in React

B. It is used to handle user interactions in React components

C. It is used to handle form submissions in React components

D. It is used to memoize functions for performance optimization

Question No# : 20 out of 50

What is the purpose of the "useEffect" hook in React?

A. To handle form submissions in React components

B. To manage the lifecycle of functional components

C. To handle user interactions in React components

D. To create reusable logic in React components

Question No# : 21 out of 50

What is used to handle code-splitting?

A. React.lazy

B. React.memo

C. React.fallback

D. React.split

Question No# : 22 out of 50

Which of the following command is used to install create-react-app?

A. npm install -f create-react-app

B. npm install -g create-react-app

C. npm install create-react-app

D. install -g create-react-app

Question No# : 23 out of 50

What changes would appear in the component as soon as the state of the React component is changed?

A. It will re-render the component

B. It can be created again from scratch

C. It will do nothing; you have to call render method to render the component again

D. None

Question No# : 24 out of 50

Which method is used to change the state of a component in React?

A. setState()

B. changeState()

C. updateState()

D. modifyState()

Question No# : 25 out of 50

Which of following is used to pass data to a component from outside?

A. PropTypes

B. setState

C. render with arguments

D. props

Question No# : 26 out of 50

How can you pass data from a parent component to a child component in React?

A. Using props

B. Using state

C. Using context

D. All of the above

Question No# : 27 out of 50

Which of the following method is not a part of ReactDOM?

A. ReactDOM.destroy()

B. ReactDOM.hydrate()

C. ReactDOM.createPortal()

D. ReactDOM.findDOMNode()

Question No# : 28 out of 50

Why is useLayoutEffect used?

A. To complete the update

B. To optimize for all devices

C. To change the layout of the screen

D. when you need the browser to paint before the effectors

Question No# : 29 out of 50

Choose the library which is most often associated with react?

A. Sinon

B. Chai

C. Jest

D. Mocha

Question No# : 30 out of 50

What is the use of “web pack” command in React.js?

A. It is a module bundler

B. The “webpack” command is used to transpile all the JavaScript down into one file

C. It runs React local development server

D. None of the above

Question No# : 31 out of 50

What is the virtual DOM in React?

A. An alternative implementation of the DOM provided by React

B. A lightweight version of the DOM used for testing purposes

C. A concept used to optimize rendering performance in React

D. None of the above

Question No# : 32 out of 50

What is the purpose of React's "memo" function?

A. It is used to create reusable custom hooks in React

B. It is used to handle form validation in React components

C. It is used to optimize the rendering performance of React components

D. It is used to handle asynchronous operations and data fetching in React components

Question No# : 33 out of 50

What is the role of a reducer in React?

A. It defines the initial state of a component

B. It determines the rendering of a component

C. It specifies the action types for handling user interactions

D. It manages the state transitions of a component based on dispatched actions

Question No# : 34 out of 50

Which of the following option is correct in the case of the Babel?

A. Babel is a Transpolar

B. Babel is a Compiler

C. All of above

D. None of above

Question No# : 35 out of 50

What is the difference between controlled and uncontrolled components in React?

A. Controlled components rely on state for managing their data, while uncontrolled components do not.

B. Controlled components allow user input to directly update the component's state, while uncontrolled components do not.

C. Controlled components are created using classes, while uncontrolled components are created using functions.

D. There is no difference; the terms are used interchangeably.

Question No# : 36 out of 50

What is the significance of the "key" prop in React when rendering a list of elements?

A. It ensures unique styling for each list item

B. It determines the order in which the list items are rendered

C. It improves the performance of rendering the list

D. It helps React identify which items have changed, been added, or been removed

Question No# : 37 out of 50

Which method in a React Component should you override to stop the component from updating?

A. willComponentUpdate

B. shouldComponentUpdate

C. componentDidUpdate

D. componentDidMount

Question No# : 38 out of 50

What is the purpose of the "React.memo" higher-order component (HOC)?

A. It is used to memoize function components for performance optimization

B. It is used to create reusable custom hooks in React

C. It is used to manage state in class components

D. It is used to handle asynchronous operations and data fetching

Question No# : 39 out of 50

What is the purpose of React's "PropTypes" library?

A. It is used to define the structure and layout of a React component

B. It is used to handle form validation in React components

C. It is used to specify the types of props that a component should receive

D. It is used to manage the state of a component

Question No# : 40 out of 50

Which of the following is used to pass data to a component from outside in React.js?

A. Render with arguments

B. PropTypes

C. SetState

D. Props

Question No# : 41 out of 50

What is the purpose of state in React?

A. To store and manage data within a component

B. To define the structure of a React component

C. To handle user interactions in a component

D. To style the components

Question No# : 42 out of 50

In React, what is the purpose of the "shouldComponentUpdate" method?

A. To determine if a component should re-render or not

B. To handle asynchronous actions and side effects

C. To define the initial state of a component

D. To handle user interactions in a component

Question No# : 43 out of 50

What is the purpose of React's "getDerivedStateFromProps" lifecycle method?

A. It is used to handle form submissions in React components

B. It is used to manage state in functional components

C. It is used to update the state of a component based on changes in props

D. It is used to handle user interactions in React components

Question No# : 44 out of 50

In React, what is the purpose of the "defaultProps" property?

A. It specifies the default values for props in a component

B. It sets the initial state of a component

C. It defines the default styling for a component

D. It determines the default behavior of a component's lifecycle methods

Question No# : 45 out of 50

What is the purpose of keys in React lists?

A. To uniquely identify elements in a list

B. To define the layout and styling of list items

C. To handle event listeners on list items

D. None of the above

Question No# : 46 out of 50

How can you access the state of a component from inside of a member function?

A. this.state

B. this.values

C. this.getState()

D. this.prototype.stateValue

Question No# : 47 out of 50

What is React Hooks in React?

A. A way to create reusable logic in functional components

B. A replacement for class components in React

C. A mechanism to manage state and lifecycle in functional components

D. All of the above

Question No# : 48 out of 50

Why is ref used?

A. to bind the function

B. to call the function

C. to directly access the DOM node

D. to refer to another JS file

Question No# : 49 out of 50

What is the purpose of React's "Fragment" component?

A. It is used to wrap multiple components within a single parent component

B. It is used to conditionally render components based on certain conditionsIt is used to create reusable UI components in React

C. It is used to create reusable UI components in React

D. It is used to render multiple elements without adding extra nodes to the DOM

Question No# : 50 out of 50

What is the purpose of React's "StrictMode"?

A. To enforce strict code quality rules in React applications

B. To enable additional debugging checks and warnings in the development mode

C. To ensure compatibility with older versions of React

D. None of the above