Support launching Shiny apps via the run button in VS Code

Is your feature request related to a problem? Please describe.

When I try to run a shiny application by clicking the Play/Run button, VS Code opens the R console and executes the line:

source("path/to/app.R", encoding = "UTF-8")

However, this does not actually run the shiny app (I tried from a standalone terminal too with the same result). Instead, it seems like I need to type runApp(path/toapp.R') manually into the VS Code terminal to actually launch the shiny application.

I tried this with a simple skeleton in a file called app.R.

library(shiny)


ui <- fluidPage(
  "Hello, world!"
)

server <- function(input, output, session) {}

shinyApp(ui, server)

Describe the solution you'd like

Something similar to the extension for Shiny for Python (and RStudio), where there is an option to added to the run button which says "Run shiny app".

Describe alternatives you've considered

Typing runApp('app.R') manually into the R console. I maybe bind a hotkey to this, but it would be convenient to have a solution that is there by default, especially when teaching with VS Code for R.

Start with the VS Code run-button path that currently executes source("app.R", encoding = "UTF-8") and compare it with the linked pyshiny-vscode extension's Shiny launch behavior. Done means an app.R Shiny example can be launched from a Run-button “Run shiny app” action, rather than requiring manual runApp('app.R').