Prior Node.js experience made this click fast.
Start by reproducing the bug and gathering error logs to understand the failure. Then systematically trace the request flow from routes to controllers, using debugging tools to isolate the faulty code. Finally, fix the issue, add tests to prevent regression, and verify the solution end-to-end.
Pro tip: Demonstrate a methodical approach by first checking the route definitions for misconfigurations like incorrect HTTP methods or missing middleware, as these are common culprits. Also, mention that you would add logging and monitoring to catch similar issues early in production.
Reproduce the bug consistently and collect error messages, stack traces, and logs to understand the symptoms. Identify the affected endpoints and expected vs. actual behavior.
Follow the request from the route definition to the controller and any middleware. Check for issues like incorrect route paths, HTTP methods, or missing middleware that could cause the failure.
Examine the controller logic for errors such as unhandled exceptions, incorrect data handling, or asynchronous issues. Use debugging tools or add temporary logging to pinpoint the exact line of failure.
Apply the fix, ensuring it addresses the root cause without introducing side effects. Write or update unit and integration tests to cover the scenario and prevent regressions.
Verify the fix in a staging environment and confirm the endpoint works as expected. Document the issue and solution for future reference and consider adding monitoring to detect similar issues.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.