Complex Problem: You Solved

Q: 𝗧𝗲𝗹𝗹 𝗺𝗲 𝗮𝗯𝗼𝘂𝘁 𝗮 𝘁𝗶𝗺𝗲 𝘆𝗼𝘂 𝘀𝗼𝗹𝘃𝗲𝗱 𝗮 𝗰𝗼𝗺𝗽𝗹𝗲𝘅 𝗽𝗿𝗼𝗯𝗹𝗲𝗺 𝗶𝗻 𝗮 𝗽𝗿𝗲𝘃𝗶𝗼𝘂𝘀 𝗽𝗿𝗼𝗷𝗲𝗰𝘁?

𝗪𝗵𝗮𝘁 𝗜 𝗦𝗲𝗲 𝗛𝗮𝗽𝗽𝗲𝗻 𝗡𝗲𝘅𝘁 (𝗘𝘃𝗲𝗿𝘆 𝗦𝗶𝗻𝗴𝗹𝗲 𝗧𝗶𝗺𝗲) Candidate: "Well, I built this React app with..." Interviewer: "No, I mean a PROBLEM. Something that was broken, users were complaining, or the business was losing money." Candidate: "Um... I guess when my components were re-rendering too much?" Interviewer: Internal eye roll

The Questions That Separate Junior Devs From Experts:

𝟭. 𝗔 𝗳𝗲𝗮𝘁𝘂𝗿𝗲 𝘆𝗼𝘂 𝗯𝘂𝗶𝗹𝘁 𝗶𝘀 𝗰𝗮𝘂𝘀𝗶𝗻𝗴 𝘁𝗵𝗲 𝗮𝗽𝗽 𝘁𝗼 𝗰𝗿𝗮𝘀𝗵 𝗳𝗼𝗿 𝟮𝟬% 𝗼𝗳 𝘂𝘀𝗲𝗿𝘀. 𝗛𝗼𝘄 𝗱𝗼 𝘆𝗼𝘂 𝗱𝗲𝗯𝘂𝗴 𝘁𝗵𝗶𝘀?

• ❌ Bad: I'd check the console...

• ✅ Good: First, I'd check error monitoring tools, reproduce the issue, then implement feature flags to isolate the problem...

𝟮. 𝗬𝗼𝘂 𝗻𝗲𝗲𝗱 𝘁𝗼 𝗮𝗱𝗱 𝗮 𝗻𝗲𝘄 𝗳𝗲𝗮𝘁𝘂𝗿𝗲 𝗯𝘂𝘁 𝘁𝗵𝗲 𝗲𝘅𝗶𝘀𝘁𝗶𝗻𝗴 𝗰𝗼𝗱𝗲 𝗶𝘀 𝗮 𝗺𝗲𝘀𝘀. 𝗪𝗵𝗮𝘁'𝘀 𝘆𝗼𝘂𝗿 𝗮𝗽𝗽𝗿𝗼𝗮𝗰𝗵?

• ❌ Bad: I'd rewrite everything...

• ✅ Good: I'd evaluate the risk versus impact, create a refactoring plan, and implement it incrementally...

𝟯. 𝗛𝗼𝘄 𝘄𝗼𝘂𝗹𝗱 𝘆𝗼𝘂 𝗵𝗮𝗻𝗱𝗹𝗲 𝗮 𝘀𝗶𝘁𝘂𝗮𝘁𝗶𝗼𝗻 𝘄𝗵𝗲𝗿𝗲 𝘆𝗼𝘂𝗿 𝗥𝗲𝗮𝗰𝘁 𝗮𝗽𝗽 𝗯𝗲𝗰𝗼𝗺𝗲𝘀 𝘀𝗹𝗼𝘄 𝘄𝗶𝘁𝗵 𝗹𝗮𝗿𝗴𝗲 𝗱𝗮𝘁𝗮𝘀𝗲𝘁𝘀?

• ❌ Bad: Use React.memo everywhere...

• ✅ Good: I'd profile the app, identify bottlenecks, implement virtualization if needed, and consider server-side solutions...

𝟰. 𝗬𝗼𝘂 𝗻𝗲𝗲𝗱 𝘁𝗼 𝗶𝗻𝘁𝗲𝗴𝗿𝗮𝘁𝗲 𝘄𝗶𝘁𝗵 𝗮 𝗽𝗼𝗼𝗿𝗹𝘆 𝗱𝗼𝗰𝘂𝗺𝗲𝗻𝘁𝗲𝗱 𝗔𝗣𝗜. 𝗪𝗮𝗹𝗸 𝗺𝗲 𝘁𝗵𝗿𝗼𝘂𝗴𝗵 𝗶𝘁.

• ❌ Bad: I'd read the docs...

• ✅ Good: I'd use tools like Postman to test endpoints and create wrapper functions with error handling.

𝗦𝘁𝗮𝗿𝘁 𝗱𝗼𝗰𝘂𝗺𝗲𝗻𝘁𝗶𝗻𝗴 𝘁𝗵𝗲𝘀𝗲 𝗡𝗢𝗪:

• A bug you fixed (What was broken? How did you find it? Impact?)

• A performance improvement (Before/after metrics)

• A feature you built (Why was it needed? Challenges faced?)

• A refactoring you did (What was the mess? How did you clean it?)