Access a server side datatable in an observe event - r

Question

I am trying to create a modal that diplays text dynamically. Below is a reprex of what I'm thinking. My actual example I am creating a datatable based on reactive user input and interacting with a sql database so creating it in global environment is not desirable. Is there an easy way I can access the dataframe within the randerDataTable? My code below creates an error because table is not a dataframe object. I know renderDataTable does not create a dataframe, rather it creates an html table. Can I still access the data similiarly to a dataframe or parse it into a dataframe?
shinyApp(
ui = basicPage(
dataTableOutput("table")
),
server = function(input, output, session) {
output$table <- renderDataTable({
t <- data.frame(
x = rep(c('dog', 'cat', 'pig'),5),
y = rnorm(15),
z = rnorm(15)
)
DT::datatable(t, rownames=F, selection = 'none', options = list('tipl')) %>%
formatStyle(3, cursor = 'pointer')})
#Display the value of the cell in a modal
observeEvent(input$table_cell_clicked, {
info = input$table_cell_clicked
# do nothing if not clicked yet, or the clicked cell is not in the 1st column
if (is.null(info$value) || info$col != 2) return()
showModal(modalDialog(
title = paste("The animal you selected is:", table$x[info$row]), #creates an error because table is not a df object. Would like to do something like this though.
paste("The value of the cell is:", info$value),
easyClose = TRUE,
footer = NULL
))
})
}
)

Answer 1

You could use a global variable for this :
server = function(input, output, session) {
global_table <- NULL
output$table <- renderDataTable({
global_table <<- data.frame(
x = rep(c('dog', 'cat', 'pig'),5),
y = rnorm(15),
z = rnorm(15)
)
DT::datatable(global_table, rownames=F, selection = 'none', options = list('tipl')) %>%
formatStyle(3, cursor = 'pointer')})
#Display the value of the cell in a modal
observeEvent(input$table_cell_clicked,{
info = input$table_cell_clicked
warning(info$row )
# do nothing if not clicked yet, or the clicked cell is not in the 1st column
if (is.null(info$value) || info$col != 0) return()
showModal(modalDialog(
title = paste("The animal you selected is:", global_table$x[info$row]),
paste("The value of the cell is:", info$value),
easyClose = TRUE,
footer = NULL
))
})
}
But it's more elegant to use a reactive to compute the data
server = function(input, output, session) {
reactive_table <- reactive(
data.frame(
x = rep(c('dog', 'cat', 'pig'),5),
y = rnorm(15),
z = rnorm(15)
))
output$table <- renderDataTable({
DT::datatable(reactive_table(), rownames=F, selection = 'none',
options = list('tipl')) %>%
formatStyle(3, cursor = 'pointer')})
#Display the value of the cell in a modal
observeEvent(input$table_cell_clicked,{
info = input$table_cell_clicked
warning(info$row )
# do nothing if not clicked yet, or the clicked cell is not in the 1st column
if (is.null(info$value) || info$col != 0) return()
showModal(modalDialog(
title = paste("The animal you selected is:", reactive_table()$x[info$row]),
paste("The value of the cell is:", info$value),
easyClose = TRUE,
footer = NULL
))
})
}