Dynamic datatable (DT) with numericInput

[jro]

I added this question to the end of the thread here:

https://groups.google.com/forum/#!topic/shiny-discuss/FeqU0AoTpz0

but maybe it was more appropriate to create a new thread since that was already answered.  

That question addressed a problem I was struggling with around re-binding when embedding numeric inputs into a datatable.  However, I still have an issue that if I dynamically regenerate the table based on a parameter changing (e.g., a number of rows slider) all of the bindings are lost when the table is redrawn.  I also tried to unbind/bindall from the js console and was still unsuccessful. I've added the "slider_num_rows" to the example code from Yihui Xie in that question to illustrate the problem in a simplified way.

(separately, the data is lost too, but I'm hoping to feed the 'value' parameter of numericInput with the current input[[...]] value once I get the binding portion working). 

I'm running with 

> packageVersion('shiny')
[1] ‘0.12.1.9001’
> packageVersion('DT')
[1] ‘0.1.30’

any ideas?

Here is the code:

# need the development version of shiny due to https://github.com/rstudio/shiny/pull/857
if (packageVersion('shiny') < '0.12.0.9003')
  devtools::install_github('rstudio/shiny')
library(shiny)
library(DT)


shinyApp(
  ui = fluidPage(
   
    # add slider to control number of rows shown in table
    sliderInput("slider_num_rows", "Num Rows", min = 0, max = 100, value = 10),
   
      DT::dataTableOutput('x1'),
    verbatimTextOutput('x2')
  ),
 
  server = function(input, output) {
    # create a character vector of shiny inputs
    shinyInput = function(FUN, len, id, ...) {
      inputs = character(len)
      for (i in seq_len(len)) {
        inputs[i] = as.character(FUN(paste0(id, i), label = NULL, ...))
      }
      inputs
    }
   
    # obtain the values of inputs
    shinyValue = function(id, len) {
      unlist(lapply(seq_len(len), function(i) {
        value = input[[paste0(id, i)]]
        if (is.null(value)) NA else value
      }))
    }
   
    # a sample data frame
    res = data.frame(
      v1 = shinyInput(numericInput, 100, 'v1_', value = 0),
      v2 = shinyInput(checkboxInput, 100, 'v2_', value = TRUE),
      v3 = rnorm(100),
      v4 = sample(LETTERS, 100, TRUE),
      stringsAsFactors = FALSE
    )
   
    # render the table containing shiny inputs
    output$x1 = DT::renderDataTable(
     
      # use slider to control number of rows shown in table
      res[1:input$slider_num_rows,], server = FALSE, escape = FALSE, options = list(
        preDrawCallback = JS('function() {
                             Shiny.unbindAll(this.api().table().node()); }'),
        drawCallback = JS('function() {
                          Shiny.bindAll(this.api().table().node()); } ')
      )
    )
    # print the values of inputs
    output$x2 = renderPrint({
      data.frame(v1 = shinyValue('v1_', 100), v2 = shinyValue('v2_', 100))
    })
  }
)

[jro]

FYI, In order to see the issue:

- type a number into a v1 numeric input.  

- verify that the number is shown on the verbatim text output table below

- change the number of rows using the slider, afterwards the table is redrawn

- type a number again into a v1 numeric input

- the verbatim text output table is no longer updated / binded as it should be