Frontend

When should you use useMemo? If an array and primitive are passed to a child component — where should useMemo be applied?

How can you optimize a scroll event handler that causes frequent re-renders? What is the difference between throttling and debounce?

You were given access to a private GitHub repository and asked to clone the project and run it. How would you approach this? What would you do first?

What can be stored in useRef instead of useState?

Have you had experience with a sluggish application due to unnecessary renders or other issues? How did you find and fix it?

A user enters a URL in the address bar and presses Enter. What critical moments might occur on their way — what could go wrong, what might slow down or cause a negative experience?

How did you detect Adblock?

Is there experience working with command line and launching projects through the terminal?

What is the difference between useRef and useState?

Why can't you just pass count as a dependency in useEffect when using setInterval? What could go wrong?

What operating system do you work on?

How to type a function that accepts an object with a guaranteed 'id' field using generics?

Event Loop — whose implementation is it and where is it located?

How did you decide where it is critically necessary to cover with tests and where it is not?

What accesses are required before cloning a repository?

What methods can be used to unload parsing? Are you familiar with the async and defer attributes for scripts?

In what order will the following code execute? (Event Loop task with console.log, setTimeout, Promise.resolve, and queueMicrotask)

What moments can cause HTML parsing to pause or slow down?

There is a React component with a counter (useState), a button that increments the counter by 1, and a list of 100 items. What happens when the button is clicked?

What is the difference between a regular array and a Set? When would a Set be better than an array?