Remove/add UI components based on number of existing UI components

shiny
,
4

After reading this it feels like it shouldn't be necessary but, here is another solution avoiding removeUI, which requires less typing:

library(shiny)

ui <- fluidPage(
  column(12,
         actionButton("add", "Add a selector"),
         actionButton("resetButton", "Reset")
  ),
  column(12, uiOutput("selectors"))
)

server <- function(input, output, session) {
  nSelectors <- reactiveVal(1L)
  
  output$selectors <- renderUI({
    Map(
      selectInput,
      inputId = paste0("selector", seq_len(nSelectors())),
      label = paste("Selector", seq_len(nSelectors())),
      choices = list(c("a", "b", "c")),
      selected = "a"
    )
  })
  
  observeEvent(input$add, {
    nSelectors(nSelectors() + 1L)
    print(paste("nSelectors:", nSelectors()))
    # print(names(input))
  })
  
  observeEvent(input$resetButton, {
    nSelectors(1L)
    print(paste("nSelectors:", nSelectors()))
    # print(names(input))
  })
}

shinyApp(ui, server)
1 Like