How to stop Rshiny refresh data before I finish multiple input selection (before I hit enter)

I have 1 input in Rshiny that needs multiple inputs:

selectInput("selected_herd", "Select Herd", selected = herds_list[1], choices = herds_list, multiple = TRUE)

In the application, while I am adding multiple herds, the app refreshes the data before I hit enter. Is there anyway to stop this? and make the app refresh data only after I finish the input list and hit enter?

In the photo attached, you can see that I am about to start entering the list of herds, but the app already refreshes the data on an empty list and show errors.

What I want is the app to show result of the previous selection(photo 2) until I finish new selection and hit enter. Anyone knows how to do this? Thank you very much!!!

The traditional way in Shiny is to add a button (or any comparable widget) that must be clicked for the input to apply. On the server side you can bind the corresponding reactives to an event (like a button press) using bindEvent(). This means that the reactive expression can only be evaluated once the event is triggered.

Since you didn't share any code, I created a simple dummy example. Note that bindEvent() can be used with any type of event, not just a button.

library(shiny)

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      fluidPage(
        selectInput(
          "select",
          label = "Select Herd",
          choices = c("BBBJ", "BBBX", "BBFC", "BBFD", "BBFG"),
          multiple = TRUE
        ),
        actionButton("go", "Apply changes")
      )
    ),
    
    mainPanel(
      uiOutput("result")
    )
  )
)


server <- function(input, output) {
  result <- reactive({
    lst <- lapply(input$select, tags$li)
    paste("Selected:<br>", do.call(tags$ul, lst))
  })
  
  output$result <- renderUI({
    HTML(result())
  }) %>%
    bindEvent(input$go)
}

runApp(shinyApp(ui, server))