R Shiny -在执行insertTab之前检查选项卡是否存在

library(shiny)

ui <- fluidPage(
  navbarPage(
    "My App",
    tabPanel("Tab 1", "Content for Tab 1"),
    tabPanel("Tab 2", "Content for Tab 2"),
    actionButton("addTab", "Add Tab")
  )
)

server <- function(input, output, session) {
  observeEvent(input$addTab, {
    # 检查选项卡是否存在
    if (!is.null(input$myTabs) && input$myTabs == "newTab") {
      return()  # 选项卡已存在，不执行插入操作
    }
    
    # 插入新的选项卡
    insertTab(inputId = "myTabs",
              tabPanel("New Tab", "Content for New Tab"),
              target = "Tab 2",
              position = "after")
  })
}

shinyApp(ui, server)