Technologies Coding Problems Bookmarks Learning Paths

Technologies Coding Problems Bookmarks Learning Paths

AI-powered interview preparation platform. Practice with curated questions, mock interviews, and personalized learning paths to crack your dream tech interview.

Quick Links

Technologies
Saved Questions
Pricing

Company

About Us
Contact Us

Legal

Privacy Policy
Terms of Use

© 2026 nextRound. All rights reserved.

What should be returned by custom hooks? | Custom Hooks | react Interview Questions | NextRound.in

Questions

8 of 14

1Implement useMediaQuery hook.

3Implement useDebounce hook.

4Implement useLocalStorage hook.

5List potential pitfalls or risks of Custom Hooks.

6What should we do in cleanup functions?

7What are the advantages of cleaning up after an effect?

8What should be returned by custom hooks?

9What is the useEffect cleanup function?

10What are the advantages of Custom Hooks?

11What should not be put into custom hooks?

12What points to note and take care of while writing custom hooks?

13When should we use a custom hook?

14Why do we need custom hooks?

react

State and Props

Class Components

Function Components

Lifecycle functions

Performance Optimisation

08 / 14

What should be returned by custom hooks?

Difficulty: 5/10

hook return values, API design, stability

Return Values: Custom hooks should return values (state variables, functions, etc.) that the consuming component can use.

Custom Hook for Fetching Data

Scenario Questions

0-2 years experience

1You're writing a simple custom hook that fetches data on mount. What should the hook return so the component can use the data and loading state?
2If you need to expose a ref to a child component via a custom hook, how would you structure the return value?

2-5 years experience

1Your team added a custom hook that returns an object with several callbacks, but the component re-renders on every render. What might be wrong with what the hook returns, and how would you fix it?

Follow-up Questions

Can you explain why returning a new object each render matters?
How would you test that the hook’s return values are stable?
What impact does the choice of return type have on TypeScript inference?

Sharethis question

Share via WhatsApp, X, Facebook, LinkedIn or copy link. Open Graph preview enabled.

2A bug appears where a component using a custom hook gets a stale value after a state update. Explain how the hook's return shape could cause this and what you would change.

5-8 years experience

1Design a custom hook for form handling that needs to expose field values, error messages, and a submit handler. Discuss the trade‑offs of returning an array vs an object, and how you’d ensure stability for consumers.
2In a large codebase, you notice many custom hooks returning raw values mixed with functions, leading to inconsistent usage. How would you refactor the return contracts to improve type safety and maintainability across teams?

8+ years experience

1Your organization is standardizing hook APIs across multiple product lines. What guidelines would you set for what a custom hook should return, considering memoization, TypeScript typing, and backward compatibility?
2A legacy custom hook returns a mutable object that callers modify, causing hidden side effects. How would you redesign its return contract to enforce immutability and avoid breaking existing consumers?