shinyWidgets::switchInput under bs_theme(version="3") vs NULL

[Polkas]

Not sure who is responsible so I create a similar issue in the bslib.

So bs_theme(version="3") should work the same as NULL for the theme argument in the shiny::fluidPage.
Unfortunately shinyWidgets::switchInput is crashing the shiny app when bs_theme(version="3") is used, and not when NULL is used.

minimal example:

library(shiny)

ui <- fluidPage(
  theme = bslib::bs_theme(version = "3"), # when NULL it is ok
  shinyWidgets::switchInput("sth", "sth")
)

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

shinyApp(ui, server)

Error message:

Listening on http://127.0.0.1:3630
Warning: Error in compile_data: Error: Undefined variable: "$secondary".
        on line 69:16 of ../../../../Library/Frameworks/R.framework/Versions/4.2/Resources/library/shinyWidgets/assets/bootstrap-switch/bootstrap-switch-3.4/bootstrap-switch.scss
        from line 11:9 of stdin
>> 			background: $secondary;

   ---------------^

  3: runApp
  2: print.shiny.appobj
  1: <Anonymous>

sessionInfo:

> sessionInfo()
R version 4.2.1 (2022-06-23)
Platform: x86_64-apple-darwin17.0 (64-bit)
Running under: macOS Monterey 12.5.1

Matrix products: default
LAPACK: /Library/Frameworks/R.framework/Versions/4.2/Resources/lib/libRlapack.dylib

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
 [1] shiny_1.7.2          ...            

loaded via a namespace (and not attached):
 [1] bslib_0.4.0     ...
[81] shinyWidgets_0.7.3 

[Polkas]

This assumption does not seem to be correct

shinyWidgets/inst/assets/bootstrap-switch/bootstrap-switch-3.4/bootstrap-switch.scss

Lines 14 to 16 in 3f886ea

	// Unnecessary in shinyWidgets
	// @import "../bootstrap-4.2.1/functions";
	// @import "../bootstrap-4.2.1/variables";

as for bslib::bs_theme(version="3") it will be not inherited with proper sass color variables.

[pvictor]

Thanks for rreporting. It seems related to SCSS variable secondary that doesn't exist in BS 3, only in BS >= 4, but it's used here in Bootstrap Switch SCSS code :

shinyWidgets/inst/assets/bootstrap-switch/bootstrap-switch-3.4/bootstrap-switch.scss

Line 69 in 3f886ea

background: $secondary;

I think it will be sufficient to create the variable here with the other

shinyWidgets/R/dependencies.R

Line 307 in 3f886ea

"danger" = "$brand-danger"

to make it work, for example with "secondary" = "$gray-base" (default to gray).

[pvictor]

That's fixed, re-install from GitHub :

remotes::install_github("dreamRs/shinyWidgets")