表呈现后将div隐藏在shiny中

我正在开发一个闪亮的应用程序,它连接到一个SQL服务器并对用户输入运行一些查询。

为了向用户显示他们的查询正在运行,我包含了一个带有旋转图标的加载消息,但是当表最终呈现时,我找不到删除该消息的方法。

这里有一个聚合和启用下载的MWE,但是消息没有被正确隐藏/显示:

if (!require('pacman')) install.packages('pacman')
p_load(shiny, shinyjs, dplyr, openxlsx)

vars_g <- c("carb", "cyl", "am")

ui <- fluidPage(
  useShinyjs(),
  title = 'mtcars',
  fluidRow(
    column(3, wellPanel(
      h1("Mtcars"),
      h2("Parameters"),
      radioButtons(
        inputId = "operation", 
        label = "Operation:", 
        choices = c("Count"), 
        selected = c("Count")
      ),
      checkboxGroupInput(
        inputId = "cols_g", 
        label = "Group by:", 
        choices = vars_g
      ),
      hr(),
      downloadButton('download', 'Download')
    )),
    column(9, wellPanel(
      h2("Vista previa"),
      div(id = "see_instructions",
          p('Select some columns on the left side'), 
          p('Then you can download the data in Excel'), 
          align = 'center'
      ),
      div(id = "see_loading",
          h1('Processing...'), 
          align = 'center'
      ),
      div(id = "see_table", 
          conditionalPanel(condition = 'output.table', tableOutput('table'))
      )
    ))
  )
)

server <- function(input, output, session) {
  data <- reactive({
    hide("see_loading")
    vars_g_2 <- input$cols_g
    if(length(vars_g_2) >= 1) {
      hide("see_instructions")
      if (input$operation == "Count") {
        if (!is.null(input$cols_g)) {
          showElement("see_loading")
          mtcars2 <- mtcars %>% 
            group_by(!!!syms(input$cols_g)) %>% 
            summarise(count = n())
        }

        show("see_table")
        hide("see_loading")
      }

      return(mtcars2)
    }
  })

  output$table <- renderTable({ data() })

  outputOptions(output, 'table', suspendWhenHidden = FALSE)

  output$download <- downloadHandler(
    filename = function() { "data.xlsx" },
    content = function(filename) {
      write.xlsx(data(), filename)
    },
    contentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
  )
}

shinyApp(ui, server)