List different ways in which we can build reusable code and promote code sharing

0-2 years experience

1. 1How would you extract a button component so it can be used on two different pages without duplicating code?
2. 2If you create a custom hook for data fetching, where do you place the file and how do you import it in a component?
3. 3What happens if you import the same component using two different relative paths in a small React app?

2-5 years experience

1. 1We need a modal that appears in several places but each usage requires slightly different styling. How would you design it for reuse and what pitfalls might you watch for?
2. 2After moving a shared utility into a new folder, the production build started throwing ‘module not found’ errors. Walk me through how you’d debug this.
3. 3Why did wrapping a list item with a higher‑order component for authentication cause unexpected re‑renders, and how would you fix it?

5-8 years experience

1. 1Our organization wants a shared component library across multiple React apps with different theming needs. How would you structure the library, handle versioning, and keep bundle impact low?
2. 2Introducing a custom‑hook library caused a memory leak in a high‑frequency component. How would you identify the leak and resolve it?
3. 3Compare using a monorepo versus separate repos for sharing UI components across teams. What are the trade‑offs in terms of CI, dependency management, and team autonomy?

8+ years experience

1. 1We have legacy codebases using class components and a new codebase using functional components with hooks. Outline a migration strategy for shared utilities and components that minimizes disruption.
2. 2Design a governance model for a company‑wide React component library that balances product‑team autonomy with consistency and long‑term maintainability.
3. 3A critical security vulnerability is discovered in a shared npm package used by dozens of services. How would you coordinate the fix and rollout across the organization?