Introducing Shiny debug mode
Shiny feels like magic until it does not. Your plot updates but your table does not. Your observer fires on load but never again. The error message is "unexpected numeric constant" three lines away from the real bug.
Shiny debug mode reads your ui and server together. It names reactives, traces what invalidates what, and flags patterns that cause double execution or stale outputs.
How to use it
- Open the playground and paste ui.R and server.R into the code context panel
- Enable Shiny debug mode from the mode selector
- Describe the symptom — not just the error string
Pro subscribers get priority latency on debug traces. Free tier users can try it within their daily message limit starting in v0.4.0.