List all the hooks available in react js and provide brief definition for each

0-2 years experience

1. 1How would you add a piece of local state to a functional component that toggles a modal open and closed? Which hook would you use and why?
2. 2If you need to run some code once after a component mounts to fetch initial data, which hook would you choose and what would the dependency array look like?
3. 3What happens if you call a hook conditionally inside an if statement? Explain the rule that prevents that.

2-5 years experience

1. 1You have a component that fetches user data in useEffect, but it keeps refetching on every render. Walk me through how you'd debug the dependency array.
2. 2When would you prefer useReducer over useState for managing form state in a medium‑sized feature? Discuss trade‑offs.
3. 3Explain how you would create a custom hook to share a WebSocket connection across multiple components, and how you'd handle cleanup.

5-8 years experience

1. 1A list component suffers from unnecessary re‑renders because a callback prop changes on each render. How would you use hooks to mitigate this and what are the performance implications?
2. 2You need to expose an imperative method (e.g., focus) from a child functional component to its parent. Which hook would you use and how would you implement it?
3. 3Describe how you would refactor a large class‑based component that uses lifecycle methods into a functional component using hooks, ensuring behavior stays identical.

8+ years experience

1. 1Your organization is migrating a legacy codebase of 200+ class components to hooks. What strategy would you propose to do this incrementally while minimizing risk?
2. 2How would you design a shared state solution across many unrelated parts of the app using hooks, and what are the considerations for scalability and testing?
3. 3When introducing a new custom hook library across multiple teams, what guidelines and patterns would you establish to keep the API stable and avoid hook misuse?