React Testing and Debugging 2

Question 1

What is the purpose of the useDebugValue hook?

Accepted Answer

Displaying a label in React DevTools for custom hooks, making debugging easier

Answer

useDebugValue adds a label visible in React DevTools next to custom hooks, helping developers understand what value a custom hook is currently holding.

Question 2

What is hydration in React?

Accepted Answer

The process of attaching React event listeners to server-rendered HTML, making it interactive on the client

Answer

Hydration takes the static HTML from server-side rendering and attaches React's event handlers and state management, making the page interactive.

Question 3

What is Suspense in React?

Accepted Answer

A component that displays fallback content while waiting for lazy-loaded components or async data to resolve

Answer

Suspense wraps components that may need time to load, displaying fallback content (like a loading spinner) until the wrapped content is ready.

Question 4

What is the Profiler in React?

Accepted Answer

A tool that measures how often a React application renders and the cost of rendering, helping identify performance bottlenecks

Answer

The Profiler API measures rendering performance, showing which components rendered, how long they took, and what caused them to render.

Question 5

What is concurrent rendering in React?

Accepted Answer

A rendering strategy that allows React to prepare multiple versions of the UI simultaneously without blocking the main thread

Answer

Concurrent rendering lets React work on multiple tasks, pause and resume work, and prioritize user interactions over less urgent updates.

React Practice Test

React Practice Test

React Testing and Debugging 2