Most of the session I assumed this utility was just given to me.
Start by clarifying the requirements and constraints of the sendAsyncMessage function, including expected inputs, outputs, error handling, and concurrency needs. Then outline a design that separates concerns: message validation, async dispatch (e.g., using promises or queues), and result handling. Finally, describe comprehensive end-to-end tests that cover success, failure, and edge cases, ensuring the tests validate the full system behavior.
Pro tip: Emphasize idempotency and observability: ensure that retries or duplicate messages don't cause unintended side effects, and include logging/metrics in the async dispatch to aid debugging in production. This shows you think beyond the happy path.
Ask questions to understand the expected behavior: Is the function part of a larger system? What are the latency and throughput requirements? How should errors be handled? This ensures you build the right thing.
Define the function's parameters and return type (e.g., a Promise). Choose an async dispatch approach: direct promise-based, message queue, or worker pool, considering trade-offs like scalability and complexity.
Write the function, ensuring it validates inputs, dispatches asynchronously, and handles errors gracefully. Incorporate idempotency keys or deduplication if needed to avoid duplicate processing.
Create tests that simulate real usage: successful message send, network failures, timeouts, invalid inputs, and concurrent calls. Use mocks or test doubles for external dependencies to isolate the system.
Reflect on the design: What are the trade-offs between different async patterns? How would you scale it? Mention monitoring, retries, and backpressure as potential enhancements.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.