Preserve custom edits in cells prior to reactive update of table

[sbihorel]

Hi,

Let's assume a rhandsontable which default content depends on a selectInput. The table is editable. Using "vanilla" coding (as illustrated below), if users edit the content of the table, then change the selection of the selectInput field, all their edits are lost.
In the example below, the table can take 2 different default contents. These default content only have one row is common ('Row1').
I am trying to find a way to preserve custom edits made in the Value column when (prior to?) the table content resets. The content of the Value column would ideally be preserved for Type's that match between the previous and new content.

The commented section represents my attempt at achieving this goal. However, uncommenting it someone breaks the reactivity chain.

Thanks in advance for your help

require(shiny)
require(rhandsontable)

server <- function(input, output, session){
  
  rTable_content <- reactive({
    if (input$select == 'A'){
      DF <- data.frame(
        'Type' = paste0('Row', 1:5),
        'Value' = rep('', 5),
        stringsAsFactors = FALSE
      )
    } else {
      DF <- data.frame(
        'Type' = paste0('Row', c(1,12:15)),
        'Value' = rep('', 5),
        stringsAsFactors = FALSE
      )
    }
    
    # # Try to keep previously entered custom value for match Type's
    # if (length(input$rTable) > 0){
    #   oDF <- hot_to_r(input$rTable)
    #   DF <- merge(DF, oDF, by = 'Type')
    #   DF$Value <- ifelse(is.na(DF[,3]), DF[,2], DF[,3])
    #   DF <- DF[, 1:2]
    # }
    
    DF
  })
  
  output$rTable <- renderRHandsontable({
    rhandsontable(
      data = rTable_content(),
      rowHeaders = NULL,
      contextMenu = FALSE,
      width = 600,
      height = 300
    )
  })
  
  output$textOuput <- renderText({
    paste(
      unlist(hot_to_r(input$rTable)),
      collapse = '; '
    )
  })  
}

ui <- function(){
  fluidPage(
    fluidRow(
      column(
        width = 12,
        selectInput(
          inputId = 'select',
          label = 'Pick one!',
          choices = LETTERS[1:2],
          selected = 'A'
        ),
        rHandsontableOutput('rTable'),
        verbatimTextOutput('textOuput')
      )
    )
  )
}

shinyApp(ui, server)

[sbihorel]

Revisiting my post and the problem in general, I found the solution by actually correcting some mistakes in the original code. The code posted below works fine.

Updating title

require(shiny)
require(rhandsontable)

server <- function(input, output, session){
  
  rTable_content <- reactive(
    {
      if (input$select == 'A'){
        DF <- data.frame(
          'Type' = paste0('Row', 1:5),
          'Value' = rep('', 5),
          stringsAsFactors = FALSE
        )
      } else {
        DF <- data.frame(
          'Type' = paste0('Row', c(1,12:15)),
          'Value' = rep('', 5),
          stringsAsFactors = FALSE
        )
      }
      
      # Try to keep previously entered custom value for match Type's
      if (length(input$rTable) > 0){
        oDF <- hot_to_r(input$rTable)
        DF <- merge(DF, oDF, by = 'Type', all.x = TRUE)
        DF$Value <- ifelse(is.na(DF[,3]), DF[,2], DF[,3])
        DF <- DF[, c(1, ncol(DF))]
      }
      
      DF
    }
  )
  
  output$rTable <- renderRHandsontable({
    rhandsontable(
      data = rTable_content(),
      rowHeaders = NULL,
      contextMenu = FALSE,
      width = 600,
      height = 300
    )
  })
  
  output$textOuput <- renderText({
    paste(
      unlist(hot_to_r(input$rTable)),
      collapse = '; '
    )
  })  
}

ui <- function(){
  fluidPage(
    fluidRow(
      column(
        width = 12,
        selectInput(
          inputId = 'select',
          label = 'Pick one!',
          choices = LETTERS[1:2],
          selected = 'A'
        ),
        rHandsontableOutput('rTable'),
        verbatimTextOutput('textOuput')
      )
    )
  )
}

shinyApp(ui, server)

[sbihorel]

Closing