Frontend

Why are CSS Modules needed? Why don't we use regular CSS?

What is reactive programming? Why is React, despite its name, considered non-reactive?

Code review of the Accordion component: identify issues and suggest improvements

Why does setState not update the value immediately? What is batching?

What is useId and what is it used for?

What is CORS? If two backend servers communicate without a browser, will CORS occur?

What is the difference between HTTP and HTTPS? What is encrypted — headers, body, or URL?

Are you familiar with the concept of an 'accordion'? How can this component be implemented without JavaScript?

In a functional React component, there are two synchronous setState calls, then an asynchronous function, then three more setState calls. How many renders will occur in React 18 and React 17? What is batching and when did it appear?

Object is passed from parent component to child via props and is stored in useMemo dependency. How many times will useMemo run? How to optimize so that useMemo recalculates only once?

How to make HTTP requests correctly in React? How is Axios better than fetch?

Code review: you have a piece of production code. Find problems and suggest improvements. Will React.memo perform memoization correctly if functions and objects are passed in props?

What is the difference between SSR and SSG?

There is an array of 10 elements, and .map() is called. What will happen if you remove the return statement from the callback?

What is bad code? How do you try not to write it?

What is useMemo used for? Provide a practical example.

What new hooks appeared in React 18?

Are you familiar with the concept of breadcrumbs? What HTML tags would you use to implement this component?

What is the difference between the array methods map() and forEach()?

Can you use an array index as a key in React? Why is it not recommended?