hide button in shindydashboard body until table is rendered - r

Question

I have a shiny app where I load a file and a tabla is rendered, I want to hid a button in the body until the table is rendered. This button is going to save the filters in a file. I am using shinySaveButton from shinyFiles because I want the user to navigate until a folder and choose a custom filename
Here is the UI
header <- dashboardHeader()
sidebar <- dashboardSidebar(
sidebarUserPanel("Test"),
sidebarMenu(
id = "tabs",
menuItem("Archivo variantes", tabName = "fileupload", icon = icon("table")),
conditionalPanel("input.tabs == 'fileupload' ",
shinyFilesButton("file", "Choose a file" , multiple = FALSE,
title = "Please select a file:",
buttonType = "default", class = NULL)#,
)
)
)
body <- dashboardBody(
tags$style(type="text/css",
".shiny-output-error { visibility: hidden; }",
".shiny-output-error:before { visibility: hidden; }"),
shinyjs::useShinyjs(),
tabItems(
tabItem(tabName = "fileupload",
fluidRow(column(12,
div(DT::dataTableOutput('tabla') %>% withSpinner(color="#0dc5c1"), style = 'overflow-x: auto'))),
fluidRow(column(2, offset = 0,
shinySaveButton('save', 'Save filters', 'Save as...') )))
)
)
ui <- dashboardPage(header, sidebar, body)
And here is the server
## Server side
server = function(input, output, session) {
options(shiny.maxRequestSize=100*1024^2)
if (!exists("default_search_columns")) default_search_columns <- NULL
volumes = getVolumes()
volumes <- c(Home = fs::path_home(), "R Installation" = R.home(), getVolumes()())
file_selected <- reactive({
shinyFileChoose(input, "file", roots = volumes, session = session)
if (is.null(input$file))
return(NULL)
print(parseFilePaths(volumes, input$file)$datapath)
return(parseFilePaths(volumes, input$file)$datapath)
})
contents <- reactive({
if (is.null(file_selected()))
return()
print(file_selected())
df <- read.delim(file_selected(), header = TRUE, stringsAsFactors=FALSE, as.is=TRUE)
return(tidyr::separate_rows(df, Gene.refGene, sep = ";"))
})
# Reactive function creating the DT output object
output$tabla <- DT::renderDataTable({
if(is.null(contents()))
return()
datos <- contents()
DT::datatable(datos,
rownames = FALSE,
style = 'bootstrap',
class = 'compact cell-border stripe hover',
filter = list(position = 'top', clear = FALSE),
escape = FALSE,
extensions = c('Buttons', "FixedHeader", "Scroller"),
options = list(
stateSave = FALSE,
autoWidth = TRUE,
search = list(regex = TRUE, caseInsensitive = TRUE),
initComplete = JS(
"function(settings, json) {",
"$(this.api().table().header()).css({'font-size': '12px'});",
"}"),
scroller = TRUE,
scrollX = TRUE,
scrollY = "600px",
deferRender=TRUE,
buttons = list('colvis', list(
extend = 'collection',
buttons = list(list(extend='csv',
filename = 'results'),
list(extend='excel',
filename = 'results')),
text = 'Download'
)),
FixedHeader = TRUE
),
callback = JS('table.page(3).draw(false); "setTimeout(function() { table.draw(true); }, 300);"')) %>% formatStyle(columns = colnames(.$x$data), `font-size` = "12px")
})
filtros <- eventReactive(input$tabla_search_columns, {
str(input$tabla_search_columns)
return(input$tabla_search_columns)
})
observeEvent(input$save,
{
observe(
if(is.null(input$tabla)) {
shinyjs::disable("save")
} else { shinyjs::enable("save") }
)
})
observe({
volumes <- getVolumes()
volumes <- c(Home = fs::path_home(), "R Installation" = R.home(), getVolumes()())
shinyFileSave(input, "save", roots=volumes, session=session)
fileinfo <- parseSavePath(volumes, input$save)
if (nrow(fileinfo) > 0) {
write.table(filtros(), fileinfo$datapath, row.names = FALSE, col.names=FALSE, quote=TRUE, sep="\t")
}
})
}
shinyApp(ui, server)
I am trying to use shinyjs::disable and shinyjs::enable but I can't make it work, the button save filters is shown before selecting a file. And I want to be hidden until the table is rendered
Any help would be appreciated

Answer 1

Shiny triggers the JavaScript event shiny:value when an output is rendered. So you can disable the button at the initialization of the app, and with the help of this JS event you can enable the button whenever the table is rendered. Here is a minimal example:
library(shiny)
library(shinyFiles)
js <- paste(
"$(document).ready(function(){",
" $('#save').prop('disabled', true);", # disable the 'save' button
"});",
"$(document).on('shiny:value', function(e){",
" if(e.name === 'table'){", # if 'table' is rendered
" $('#save').prop('disabled', false);", # then enable the 'save' button
" }",
"});"
, sep = "\n"
)
ui <- fluidPage(
tags$head(tags$script(HTML(js))),
shinySaveButton("save", "Save", "Save file"),
actionButton("go", "Render table"),
tableOutput("table")
)
server <- function(input, output){
output[["table"]] <- renderTable({
req(input[["go"]]>0)
iris[1:4, ]
})
}
shinyApp(ui, server)