[Feature Request]: teal::init to return shinyApp instead of a list

[gogonzo]

teal::init to return "teal_app" object (simple S3 class). For this class we can have a print method which can look as follows:

print.teal_app <- function(x, ...) {
  cat("teal app <more information about the app>")
  shiny::shinyApp(x$ui, x$srv) 
}

Thanks to above "teal_app" object will preserve previous features (list of ui, server, ui_args, ... etc) and could be run without shinyApp(x$ui, x$server) . This would shorten the apps code:

# from
app <- teal::init(...)
shinyApp(app$ui, app$server)

# to
teal::init(...)

With the S3 class first and the second in above code would be possible.

Alternatively, print.teal_app could just print information about the app with note use shinyApp(x$ui, x$server) to run the app.

Please note that shiny works in very similar way https://github.com/rstudio/shiny/blob/370ba1f288d3f759456ef3ef6e768ee1d7fda677/R/shinyapp.R#L552

[chlebowa]

Do you mean just adding shinyApp(ui = res$ui, server = res$server) as the return value of init?

Nothing will be broken due to this,

Besides the fact that you can't do shinyApp(app$ui, app$server) anymore, do I have this correct?

[pawelru]

This is a potentially breaking change and if done (which I am still not sure about) it would be better to go through the formal deprecation process

[gogonzo]

@chlebowa @pawelru true, I have not noticed shinyApp doesn't return a list. Forget about this.

---

Initially I thought that teal::init can return list(ui = ui, server = sever, class = "teal.app") and we can have a print.teal.app which runs the app. Since it is not so easy I don't push for this and I suggest to refine this first ;)

[vedhav]

I don't think we should return shiny.appobj from teal::init() if we did this we would have to support other arguments to be passed into init like enableBookmarking. I misinterpreted the feature request when I first read it. I just thought that we're replacing the runApp(app) into shinyApp(app$ui, app$server) in all examples where we use the former as it is meant for interactive calling of shiny app and has known problems when it comes to deployment.

[gogonzo]

The idea doesn't make sense. Let's pay attention to https://github.com/insightsengineering/teal/issues/1448