R Shiny中嵌入{daff}HTML输出时action button仅单次生效问题

• daff::render_diff默认输出包含<html>、<head>、<body>等根标签的完整HTML文档，直接插入Shiny页面后会破坏原有DOM结构，导致Shiny的事件绑定失效，因此第一次弹出模态框后，后续点击保存按钮无响应
• 模态框仅展示文本或普通表格时，不存在完整HTML结构冲突，因此功能可正常运行

仅需裁剪daff输出的内容，仅保留对比表格的核心片段即可解决冲突：

library(shinydashboard)
library(daff)
library(dplyr)
library(DataEditR)

df1 = iris %>% slice(1:10) %>% select(-Species)
df2 = iris %>% slice(1:12)

# Define UI
ui = shinyUI(
  fluidPage(
    fluidRow(
      box(
        title = "First data",
        status = "success",
        width = 6,
        solidHeader = TRUE,
        collapsible = TRUE,
        dataEditUI(id = "old_data")
      ),
      box(
        title = "New data",
        status = "primary",
        width = 6,
        solidHeader = TRUE,
        collapsible = TRUE,
        dataEditUI(id = "new_data"),
        br(),
        actionButton("save", "Save!")
      )
    )
  )
)

# Define server
server = shinyServer(function(input, output, session) {
  
  data_old = dataEditServer(
    "old_data",
    data = df1, 
    col_readonly = names(df1),
    col_names = FALSE,
    col_options = TRUE,
    row_edit = FALSE
  )
  
  data_new = dataEditServer(
    "new_data",
    data = df2, 
    col_names = FALSE,
    col_options = TRUE,
    row_edit = FALSE
  ) 
  
  diff_data = reactive({
    full_html <- daff::render_diff(
      daff::diff_data(
        data_old(),
        data_new()
      ), view = FALSE
    )
    # 仅提取body内的对比表格内容，丢弃外层完整HTML结构避免DOM冲突
    gsub("^.*<body>(.*)</body>.*$", "\\1", full_html)
  })
  
  output$compare_df = renderUI({
    HTML(
      diff_data()
    )
  })
  
  observeEvent(
    input$save, {
      showModal(
        modalDialog(
          span(
            "Check modification before validation!",
            style = "color: red; font-size: 130%;"
          ),
          br(),
          br(),
          uiOutput("compare_df"),
          footer = tagList(
            modalButton("Cancel"),
            actionButton("ok", "OK")
          ),
          easyClose = TRUE,
          size = "l"
        )
      )
    }
  )
  
  observeEvent(
    input$ok, {
      print(data_new())
      removeModal()
    }
  )
  
})

shinyApp(ui, server)

内容的提问来源于stack exchange，提问作者Mostafa90