How do I answer 'How would you scale this for 10,000 items?' in a machine coding follow-up?
Discuss virtualization (render only visible items with react-window or react-virtualized), pagination, lazy loading, and efficient data structures. Explain that rendering 10,000 DOM nodes is slow, and virtualization solves it by rendering only the visible ones.
Verify This Answer
Cross-check this information using these trusted sources:
More FAQs in Machine Coding Round: Follow-Up Questions to Expect
How would you scale for 10,000 items (virtualization)? How would you optimize performance (debounce, memo)? How would you make it accessible (ARIA)? How would you test it? Why did you structure the code this way? What would you do differently with more time?
Discuss ARIA roles, keyboard navigation (tab, arrow keys, enter, escape), screen reader support, focus management, and semantic HTML. Explain that accessibility is not optional and benefits all users.
Discuss unit tests (Jest, React Testing Library) for logic and rendering, integration tests for component interaction, and E2E tests (Cypress, Playwright) for user flows. Mention testing edge cases and accessibility.
Still have questions?
Browse all our FAQs or reach out to our support team