query an arbitrary html element, e.g. to see if it is disabled, with shinyjs

Question

Can shinyjs do something like if(is_disabled("#my_element_id")) do_something() ? I'd like to be able to see if a specific HTML element is disabled (by shinyjs or other means) before doing something else with it.

Answer 1

There's no such function. The answer depends on what you want exactly. Here is something which could help:

library(shiny)
library(shinyjs)

jsCode <- 'shinyjs.isDisabled = function(params) {
  var el = $("#radiobtns");
  Shiny.setInputValue("disabled", el.prop("disabled"));
}' 

ui <- fluidPage(
  useShinyjs(),
  extendShinyjs(text = jsCode, functions = "isDisabled"),
  actionButton("button", "Disable radio buttons"),
  radioButtons("radiobtns", "Radio buttons", c("Yes", "No"))
)

server <- function(input, output) {

  observeEvent(input$button, {
    toggleState("radiobtns")
    js$isDisabled()
  })

  observeEvent(input$disabled, {
    if(input$disabled){
      cat("disabled\n")
    }else{
      cat("enabled\n")
    }
  })

}

shinyApp(ui = ui, server = server)