This one took me longer than I expected to even scope.
Start by clarifying requirements and edge cases, then outline a modular design that separates retry policy, timeout handling, and cancellation. Implement the wrapper with composable pieces, and discuss trade-offs like backoff strategies and error filtering.
Pro tip: Emphasize idempotency and the importance of not retrying non-idempotent operations without safeguards; also mention that you'd use AbortController to cancel in-flight attempts and avoid resource leaks.
Ask about expected use cases, error types, and whether the function is idempotent. Confirm details like default retry count, backoff parameters, and timeout behavior.
Define the wrapper signature and options object (e.g., retries, backoff, timeouts, signal, retryableErrors). Ensure it works for both sync and async functions by normalizing to promises.
Create a loop that attempts the function, catches errors, and decides whether to retry based on the error filter. Calculate delay using exponential backoff with cap and optional jitter.
Use Promise.race or AbortController to enforce per-attempt and overall timeouts. Propagate cancellation to the underlying function via the signal.
Cover scenarios like non-idempotent operations, memory leaks from unhandled timers, and how to handle errors that occur during backoff delays. Mention testing strategies.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Cross-field validation sounds routine until you actually think about when to revalidate.
Start by clarifying requirements and constraints, then design a component with controlled inputs and a validation system that runs on every change. Implement per-field length validators and a cross-field uniqueness validator, ensuring that changing any field triggers revalidation of all fields. Discuss trade-offs between validation strategies and how to handle performance and user experience.
Pro tip: Emphasize that validation should be debounced or run on blur for better UX, but for cross-field constraints, immediate revalidation on change is necessary to keep the form consistent. Also, consider using a validation library or a custom hook to encapsulate logic and avoid duplication.
Ask about the expected behavior: should validation run on every keystroke or on blur? What are the min/max defaults? Should errors be displayed per field or globally? Are there performance concerns with frequent revalidation?
Outline a controlled component with state for each field's value and errors. Use a single source of truth for form state, and plan to lift validation logic into a custom hook or utility function for reusability.
Create a length validator that checks each field against configurable min/max. Create a uniqueness validator that compares all pairs of fields. Ensure validators return clear error messages and are composable.
When any field changes, re-run all validators (or at least the affected ones) to update errors. Discuss strategies to avoid infinite loops and ensure efficient re-renders, such as using useEffect or a validation schema.
Talk about performance implications of revalidating all fields on every keystroke, and consider debouncing or validating on blur for length checks while keeping uniqueness checks immediate. Address edge cases like empty fields, whitespace, and case sensitivity.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.