Would love the checkboxGroupInput to (optionally) have a select all/select none box associated with the group.
I think you can achieve this by updateCheckboxGroupInput(). An example:
myChoices <- letters[1:5]
runApp(list(
  ui = basicPage(
    checkboxGroupInput('foo', 'FOO', myChoices),
    checkboxInput('bar', 'All/None')
  ),
  server = function(input, output, session) {
    observe({
      updateCheckboxGroupInput(
        session, 'foo', choices = myChoices,
        selected = if (input$bar) myChoices
      )
    })
  }
))
                    I love this! An elegant solution!
Could it be relevant to reopen that suggestion?
When using shiny with flexdashboard, it would be easier for basic users to have a simple option directly within checkboxGroupInput ().
Best regards
Most helpful comment
I think you can achieve this by
updateCheckboxGroupInput(). An example: