React Js Online Test

1. Which cloud service providers offer serverless computing platforms?

AWS Lambda and Azure Functions React and Angular Express and Django MongoDB and PostgreSQL

2. What is the main purpose of code splitting in a React application?

To reduce the size of the initial bundle To increase development speed To improve SEO To manage state

3. In React, what is the first method called during the component lifecycle?

componentDidMount render componentWillUnmount constructor

4. Which React element type is commonly used to render conditional content based on a condition?

<Conditional> <div> <span> <Fragment>

5. Which of the following is NOT a common state management library for React?

Redux MobX GraphQL Zustand

6. Which directory is commonly used for storing test files in a React project?

tests src public node_modules

7. In React, what is a "test double" or "mock"?

A component that renders other components A fake implementation of a dependency A type of test suite A test report

8. In SSR, when is the initial rendering of a React component performed?

On the server On the client On both the server and client Only in modern browsers

9. How does React determine when to load a lazily loaded component?

When it's explicitly requested by the user When it's mentioned in package.json When it's defined in the index.html When the component is imported

10. When using Styled Components in React, how are styles defined for a component?

As tagged template literals As JSX attributes As function expressions As JSON objects

11. Which virtual DOM library is used by React.js?

jQuery Vue.js ReactDOM Redux

12. What is the purpose of the "serverless.yml" configuration file in a serverless application?

To define serverless functions and resources To store API endpoints To configure Webpack settings To manage database connections

13. Which Redux function is used to dispatch actions to update the state in a Redux store?

getState dispatch subscribe mapStateToProps

14. What is one key advantage of using props and state in React components?

Improved performance Component reusability Tighter security Server-side rendering

15. What is React Native primarily used for?

Web development Mobile app development Desktop application development Game development

16. What is the key benefit of using functional components in React?

They can have their own state They have better performance than class components They support lifecycle methods They can't be reused

17. Which of the following is NOT a valid Route component prop in React Router?

path component render click

18. What is the primary function of React Router in a React application?

To handle server requests To create reusable UI components To manage client-side routing To manage API requests

19. When rendering a list of React components, what should the "key" prop be set to?

The component's index in the list A unique identifier for each component The component's type The component's name

20. What is a unit test in the context of React testing?

A test that verifies the entire application A test that checks a single unit of code A test that simulates user interactions A test that checks for memory leaks