Copied the logic from radioButton to updateRadioButton

[ColinFay]

this will close #3064

[wch]

With the other PR, this will be "length 0 or 1." We might as well add that text now.

Also, this should be warning() instead of stop(). This is because this function will typically be called from an observer, and if there's a stop() in an observer, it will stop the entire application -- and that could stop it for multiple users.

[ColinFay]

In the logic implemented in the other PR, length 0 will be authorized: it will set all buttons to unselected, so I'm not sure about changing the test/text?

My choice for a stop() was that if you do updateRadioButtons(session, "radio", selected = letters[5:10]) for example, nothing is happening.

pkgload::load_all()

ui <- fluidPage(
  radioButtons("radio", "Radios", letters),
  actionButton("change", "Change")
)

server <- function(input, output, session) {
  
  
  observeEvent(input$change, {
    # This part doesn't do anything
    updateRadioButtons(session, "radio", selected = letters[5:10])
  })
  
}

shinyApp(ui, server)

Error in the JS console:

shiny.min.js:3 Uncaught TypeError: t.replace is not a function
    at exports.$escape (shiny.min.js:3)
    at exports.InputBinding.setValue (shiny.min.js:3)
    at exports.InputBinding.receiveMessage (shiny.min.js:3)
    at ShinyApp.<anonymous> (shiny.min.js:3)
    at ShinyApp._sendMessagesToHandlers (shiny.min.js:3)
    at ShinyApp.dispatchMessage (shiny.min.js:3)
    at WebSocket.n.onmessage (shiny.min.js:3)

Maybe another logic then would be to take the last element of selected then? This would match the behavior of updateSelectInput:

ui <- fluidPage(
  selectInput("select", "Select", letters),
  actionButton("change", "Change")
)

server <- function(input, output, session) {
  
  
  observeEvent(input$change, {
    # This will make select be 'j', the last element of `letters[5:10]`
    updateSelectInput(session, "select", selected = letters[5:10])
  })
  
}

shinyApp(ui, server)

Or the first, then matching the behavior of updateSliderInput

ui <- fluidPage(
  sliderInput("slider", "slider", 1, 10, 4),
  actionButton("change", "Change")
)

server <- function(input, output, session) {
  
  
  observeEvent(input$change, {
    # This will make slider be 1
    updateSliderInput(session, "slider", value = 1:3)
  })
  
}

shinyApp(ui, server)

Which raises another question: shouldn't both behave the same way (i.e either taking the first or the last)?

[ColinFay]

@schloerke any reason for closing this PR?

[schloerke]

@ColinFay I can not manually change the base merge branch. 😞

Do you mind resubmitting the PR? Sorry for the hassle