Shiny: What is the option setting to display in the console the messages between server and ui

Question

I remember having used an option setting that enable to print in the R console the messages between the server and ui while a shiny app is running. This option is really use

Answer 1

I finally found it :

options(shiny.trace=TRUE)

Before running the app. I find it extremely useful to understand what is appending. I don't know why it is not more documented.

Answer 2

R Studio lists a nice summary of R Shiny global options available here

You may wish to turn both of these on: options(shiny.trace=TRUE) options(shiny.fullstacktrace=TRUE)