Frontend

What is Teleport in Vue 3 and how is it used?

Your branch is behind dev because another developer has already merged their changes. How to update your branch and resolve conflicts?

Add a retry mechanism to the once function: if the asynchronous function fails, retry the call a specified number of times (the number of attempts is passed as the second parameter).

Middle

Okko

How do you copy an object (non-primitive type) so that changes in the copy do not affect the original?

How does MVCC work in PostgreSQL? Why is versioning needed?

Tell me about fragments and portals in React.

Middle

Wildberries

Have you ever worked with Profiler in React DevTools?

What are state managers used for and how do they differ from using Context?

Why do we access the value through .value when using ref?

Will you be able to work in an office after returning to Moscow?

Implement a memoization function: it takes a function and returns its wrapper that caches call results by arguments.

Has there ever been a case where A/B testing failed and the new interface turned out to be worse?

Tell me about the principles of OOP

Is useCallback needed here? What is it used for and when does its use make no sense?

How many teams were involved in the product, how many people were in your team, and how many developers worked on one micro frontend?

/** * Checks whether brackets are balanced in a string. * Brackets that may appear in the string: * [[{ and }]] * @param {string} str * @return {boolean} */ function parentheses(str) { const open = ['(', '[', '{']; const close = [')', ']', '}']; const stack = []; for (let i = 0; i < str.length; i++) { const letter = str[i]; if (open.includes(letter)) { stack.push(letter); } else if (close.includes(letter)) { const index = close.indexOf(letter); const lastOpenIndex = stack.length - 1; if (open[index] !== stack[lastOpenIndex]) { return false; } else { stack.splice(lastOpenIndex, 1); } } } return stack.length === 0; }

At what event phase does the handler added via addEventListener trigger by default?

How to call a child component's method from a parent component in Vue.js?

const createCounter = () => {

Middle+

IT One

How to understand that the backend is working poorly, where is it slowing down? How to debug a 500 error in production?