Passing input$ value to JS() statement in shiny da

问题:

Using this code to format the rows in my datatable

 rowCallback = DT::JS(
      'function(row, data) {
        // Bold cells for those >= 5 in the first column
        if (parseFloat(data[0]) >= 5.0)
          $("td", row).css("background", "red");
      }'
    )

I would like to alter this code so that rather than the static "5.0" value, highlighting is based on an an input$ value. So that users could click on a point on the chart, and rows with that value would be highlighted in the data table.

But substituting input$click for 5 doesn't seem to work. Thoughts?

rowCallback = DT::JS(
          'function(row, data) {
            // Bold cells for those >= 5 in the first column
            if (parseFloat(data[0]) >= input$click)
              $("td", row).css("background", "red");
          }'
        )

回答1:

Using the newest version of DT, you can do this without any Javascript using formatStyle.

Here's an example:

library(shiny)
library(DT)
shinyApp(
        ui = fluidPage(numericInput("cutoff", "Test", 5, min = 0, max = 10, step = 1),
                       DT::dataTableOutput('tbl')
        ),
        server = function(input, output) {
                output$tbl = DT::renderDataTable(
                        datatable(iris, options = list(lengthChange = FALSE)) %>% formatStyle(
                                'Sepal.Length',
                                target = 'row',
                                backgroundColor = styleInterval(input$cutoff, c('gray', 'yellow'))
                        )
                )
        }
)

More info and examples here and here.

You will probably need to install the development version of DT by running:

devtools::install_github('rstudio/DT')

If you can't use the dev version of DT, here's another solution:

library(shiny)
library(DT)
shinyApp(
        ui = fluidPage(numericInput("cutoff", "Test", 5, min = 0, max = 10, step = 1),
                       uiOutput("tbl_holder")

        ),
        server = function(input, output) {
                output$tbl_holder <- renderUI({
                        DT::dataTableOutput('tbl')
                })

                output$tbl = DT::renderDataTable(
                        datatable(iris, options = list(lengthChange = FALSE,rowCallback = DT::JS(
                                paste0('function(row, data) {
                                // Bold cells for those >= 5 in the first column
                                if (parseFloat(data[0]) >=',input$cutoff,')
                                $("td", row).css("background", "red");
        }')
        )))) 
        }
)

You can use paste to add the cutoff in the JS function and renderUi/uiOutput so that the function that prints the datatable is updated each time the cutoff changes.