Step through debugger

Before I step through, make the debugging session easy to follow for Jake: highlight the current source file and line, show the local variables pane prominently, and keep breakpoints visible. If any inline source differs from disk, flag it. Stop stepping into third‑party library files unless a project file is involved. Ladder L2

The program paused on the breakpoint inside handleUserRequest; the user id is undefined but I expected a string. I do not know whether the undefined came from earlier parsing or from this function’s argument wiring. Which is the most likely cause and what should I do next to confirm — add a breakpoint earlier at request parsing, inspect the call site, or log the caller’s value? Ladder L5

Every week I spend an hour stepping through stack frames to find where nulls originate. I keep restarting, miss the caller’s context, and reintroduce the bug in later fixes. What habit will reduce this debugging churn — better preconditions, more unit tests around the parser, adding strategic breakpoints at call sites, or using watch expressions? Recommend the single most effective change and the quick discipline to adopt now. Ladder L6