Detecting whether shiny runs the R code

Question

I would like to run R code in two locations, in an Rnw file and as an interactive shiny R markdown document.

Thus, what I need, since interactive shiny components do not work in Rnw files, is a code snippet in R that detects whether to load the interactive code or not.

This seems to work, but it feels like a quick hack:

if (exists("input")) { # input is provided by shiny
    # interactive components like renderPlot for shiny
} else {
    # non-interactive code for Rnw file
}

Is there a stable solution or something like a global variable that I can access that says whether shiny is running at the moment? Or should I check whether the shiny package is loaded?

What's safest?

Answer 1

There is now a function shiny::isRunning().