React Routing and Performance

Question 1

What is React Router?

Accepted Answer

A library for handling navigation and URL routing in single-page React applications

Answer

React Router enables navigation between views/pages in a React SPA by mapping URL paths to components without full page reloads.

Question 2

What is lazy loading in React?

Accepted Answer

Loading components or code only when they are needed rather than all upfront, improving initial load time

Answer

React.lazy() enables code splitting by loading components dynamically when they are first rendered, reducing the initial bundle size.

Question 3

What is React.memo?

Accepted Answer

A higher-order component that prevents re-rendering when props have not changed, optimizing performance

Answer

React.memo memoizes a component, skipping re-render if its props have not changed. This is useful for expensive-to-render components.

Question 4

What is the useCallback hook?

Accepted Answer

A hook that memoizes callback functions, preventing their recreation on every render unless dependencies change

Answer

useCallback returns a memoized version of a callback that only changes when dependencies change, useful for preventing unnecessary re-renders of child components.

Question 5

What is code splitting?

Accepted Answer

Breaking the application bundle into smaller chunks that load on demand, reducing initial page load time

Answer

Code splitting divides the JavaScript bundle into smaller pieces. Only the code needed for the current view loads initially, with other chunks loaded as needed.

React Practice Test

React Practice Test

React Routing and Performance