R shiny 和 DT 不使用具有某些 DT 选项的特定列的列宽集呈现

Question

I have this piece of code. The DT datatable does not render at all. It shows the columns, and nothing else. I posted a related question earlier, but apparently, this issue needed to be posted as a separate question. I am.

Any idea of what I am missing?

library(dplyr)
library(shiny)
library(DT)
library(data.table)

mtcars <- mtcars[1:5, ]

ui <- fluidPage(
  fluidRow(
    dataTableOutput(('mtcarsDT')),
    )
  )

server <- function(input, output, session) {
  output$mtcarsDT <- DT::renderDataTable({
    recFeedbackCol <- lapply(1:nrow(mtcars), function(recnum)
      as.character(
        radioButtons(
          paste0(
            'rec', recnum),
          '',
          choices = c('good' = 'Good', 'bad' = 'Bad', 'neutral' = 'Neutral'),
          inline = TRUE
        )
      )
    )
    recFeedbackCol <- tibble(feedback = recFeedbackCol)
    
    mtcars <- bind_cols(
      mtcars,
      recFeedbackCol
      )
    
    mtcars %>%
      DT::datatable(
        extensions = 'FixedColumns',
        rownames = FALSE,
        escape = FALSE,
        class="compact cell-border",
        options = list(
          pageLength = 15, 
          lengthChange = FALSE, 
          scrollX = TRUE,
          searching = FALSE,
          dom = 't',
          ordering = TRUE,
          fixedColumns = list(leftColumns = 2),
          preDrawCallback = JS(
            'function() { Shiny.unbindAll(this.api().table().node()); }'
          ),
          drawCallback = JS(
            'function() { Shiny.bindAll(this.api().table().node()); } '
          ),
          autoWidth = TRUE,
          columnDefs = list(
            list(width = '200px', targets = ncol(mtcars))
          )
        )
      )
    })
  }

shinyApp(ui = ui, server = server)

Answer 1

The problem seems to be targets parameter of columnDefs . It accepts column index starting from 0. To specify the last column, it needs to be reduced by 1.

  columnDefs = list(
    list(width = '200px', targets = ncol(mtcars) - 1)
  )