The package shinyDebuggingPanel has been updated to version 0.3,
with a better interface and line counters to recall previous commands.
To check it out,
devtools::install_github('professorbeautiful/shinyDebuggingPanel')
library(shinyDebuggingPanel)
testDebuggingPanel()
Put a shinyDebuggingPanel into your app (straight shiny or Rmarkdown shiny).
You can then type some code into the box, either R or JS,
and execute it while the app is running.
(Deployment of an app on shinyapps.io seems to prevent a bad actor from
abusing it... or at least they make trouble-making exploitation difficult.)
In developing new apps, I'd be lost without this thing.