Obtain Shiny's Bootstrap Sass theme

getCurrentTheme()

Intended for use by Shiny developers to create Shiny bindings with intelligent styling based on the bootstrapLib()'s theme value.

If called at render-time (i.e., inside a htmltools::tagFunction()), and bootstrapLib()'s theme has been set to a bslib::bs_theme() object, then this returns the theme. Otherwise, this returns NULL.