React Patterns and Code Organization Questions

Covers common React development patterns best practices and project organization principles to build maintainable and performant user interfaces. Topics include component design and composition, conditional rendering and list rendering with keys, hooks and custom hooks patterns, state management strategies and avoiding prop drilling, context usage, memoization and performance optimizations, file and folder organization conventions, naming and code style, testing components and integration points, accessibility considerations, and trade offs for applying patterns in different application sizes.

EasyTechnical

51 practiced

List and briefly explain common conditional rendering patterns in React: ternary operator, logical && short-circuiting, IIFE (immediately-invoked function expressions) inside JSX, and Higher-Order Components or render props. Provide short code snippets showing idiomatic usage and pitfalls (for example, falsy values rendered with &&).

HardTechnical

49 practiced

Explain React concurrent rendering tools that improve UI responsiveness: useTransition, startTransition, useDeferredValue, and how Suspense can be used for data fetching. Give an example where you move a heavy non-urgent update (like filtering a large list) to a transition to keep input responsive and describe how you'd measure improvement.

MediumTechnical

56 practiced

How would you unit test a custom hook that consumes a Context and performs data fetching? Describe the testing tools and approach (renderHook or test component), how to mock network requests (MSW vs jest mocks), how to provide context values to the hook during tests, and what edge cases to assert (loading, success, error, unmount cleanup).

HardSystem Design

53 practiced

Design a micro-frontend architecture for multiple independent teams building React features. Compare approaches (Webpack Module Federation vs iframes vs web components), discuss shared dependency management (avoid duplicate React), routing composition, cross-app communication patterns, deployment independence, and strategies to avoid CSS collisions and runtime performance pitfalls.

EasyTechnical

56 practiced

What does React.memo do and when is it useful? Explain with a small component example how React.memo prevents unnecessary re-renders by using shallow prop comparison. Also describe cases where wrapping with memo yields no benefit or can hurt performance (e.g., cheap renders or frequently changing function props).

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