Stack trace debugger
ProblemA stack trace points at a line, not at the cause, and searching the error message wastes an hour.
TypeError: Cannot read properties of undefined (reading 'map') at OrderList.tsx:14
Root cause: orders is undefined on first render — the fetch hasn't resolved.
Fix: const orders = data?.orders ?? []
Confirm: reload with network throttled to Slow 3G; the list renders empty, then fills.
Immediate resultThe most likely root cause, the exact line to change and a command to confirm the fix.


