jquery - R Shiny: table conditional formatting within renderUI

Question

In another post the same question has been answered assuming that the table is not part of a renderUI function.

In the below example I am trying to adjust the same solution (using JQuery) where the table I want to conditionally format belongs in a renderUI function.

    library(shiny)
    library(datasets)

    script <- "$('tbody tr td:nth-child(5)').each(function() {

              var cellValue = $(this).text();

              if (cellValue > 50) {
                $(this).css('background-color', '#0c0');
              }
              else if (cellValue <= 50) {
                $(this).css('background-color', '#f00');
              }
            })"

  shinyServer(function(input, output, session) {

    session$onFlushed(function() {
      session$sendCustomMessage(type='jsCode', list(value = script))
    })

    output$view <- renderTable({
      head(rock, n = 20)
    })

    output$Test1 <- renderUI({
      list(
        tags$head(tags$script(HTML('Shiny.addCustomMessageHandler("jsCode", function(message) { eval(message.value); });'))),
        tableOutput("view")
      )
    })
  })

  shinyUI(fluidPage(

    tabsetPanel(
      tabPanel("Test1",uiOutput("Test1")),
      tabPanel("Test2")
    )
  ))

In this small example conditional formating is not applied to the table

Answer 1

Change your call to session$onFlushed to call your function every time shiny flushes the reactive system by adding the argument once = FALSE:

  session$onFlushed(function() {
    session$sendCustomMessage(type='jsCode', list(value = script))
  }, once = FALSE)

in a self contained example:

library(shiny)
library(datasets)
script <- "$('tbody tr td:nth-child(5)').each(function() {
var cellValue = $(this).text();
if (cellValue > 50) {
$(this).css('background-color', '#0c0');
}
else if (cellValue <= 50) {
$(this).css('background-color', '#f00');
}
})"
runApp(list(server = function(input, output, session) {
  session$onFlushed(function() {
    session$sendCustomMessage(type='jsCode', list(value = script))
  }, FALSE)
  output$view <- renderTable({
    head(rock, n = 20)
  })
  output$Test1 <- renderUI({
    list(
      tags$head(tags$script(HTML('Shiny.addCustomMessageHandler("jsCode", function(message) { eval(message.value); });')))
      , tableOutput("view")
    )
  })
}
, ui = fluidPage(

  tabsetPanel(
    tabPanel("Test1",uiOutput("Test1")),
    tabPanel("Test2")
  )
))
)