how to make a copy of a reactive value in shiny server function

Question

I am building a Shiny app and using the code from this question as an example: How to download editable data table in shiny. However, in my code the df <- reactiveVal(dat) does not work, because the dat itself is already a reactive value that comes from an eventReactive({}) function. This is the code I am working with, it works if I define the dat outside of the server, but not when it is created inside the server function of shiny. How do I make a copy of it so that I can show it in a new table (and potentially process further and download in later steps in the app)?

library(shiny)
library(DT)
library(shinyWidgets)


# if the data frame is just an object, it works
#dat <- iris[1:3, ]

ui <- fluidPage( actionBttn(
  inputId = "btnProcess",
  label = "Process",
  size = "sm",
  color = "success"
),
  DTOutput("my_table"),
  DTOutput("table2")
  
)

server <- function(input, output){
  
  
  # if the dataframe is a reactive variable, this doesnt work.
  dat <- eventReactive(input$btnProcess, {
    iris[1:3, ]
  })
  
  
  output[["my_table"]] <- renderDT({
    datatable(dat(), editable = "cell")
  })
  
  
  #############################
  #### none of these work #####
  #############################
  
  #df <- reactiveVal(dat)
  #df <- reactiveVal(dat())
  #df <- dat()
  #df <- dat
  
  
  observeEvent(input[["my_table_cell_edit"]], {
    cell <- input[["my_table_cell_edit"]]
    newdf <- df()
    newdf[cell$row, cell$col] <- cell$value
    df(newdf)
  })
  
  
  output[["table2"]] <- renderDT({
    datatable(df())
  })
  
  
}

shinyApp(ui, server)

YBS · Accepted Answer · 2021-02-22T16:04:23.880

Try this

ui <- fluidPage( actionBttn(
  inputId = "btnProcess",
  label = "Process",
  size = "sm",
  color = "success"
), 
actionBttn(inputId = "reset", label = "Reset", size="sm", color="warning"),
DTOutput("mytable"),
DTOutput("table2")

)

server <- function(input, output){
  
  
  # if the dataframe is a reactive variable, this doesnt work.
  dat <- eventReactive(input$btnProcess, {
    iris[1:3, ]
  })
  
  mydf <- reactiveValues(data=NULL)
  
  observe({
    mydf$data <- dat()
  })
  
  output$mytable <- renderDT({
    datatable(mydf$data, editable = "cell")
  })
  
  observeEvent(input$mytable_cell_edit, {
    info = input$mytable_cell_edit
    str(info)
    i = info$row
    j = info$col
    v = info$value
    
    mydf$data[i, j] <<- DT::coerceValue(v, mydf$data[i, j])
    
  })
  
  output[["table2"]] <- renderDT({
    datatable(mydf$data)
  })
  
  observeEvent(input$reset, {
    mydf$data <- dat()   ## reset it to original data
  })
  
}

shinyApp(ui, server)

If I add this and change anything to the code, it still gives an error — Gh_Shiny, Feb 22 '21 at 14:47
Than you!, I now also have a short follow up question for which I opened a new question: https://stackoverflow.com/questions/66333176/how-to-make-a-copy-of-reactive-table-in-r-shiny-in-reactivevalues — Gh_Shiny, Feb 23 '21 at 12:34

how to make a copy of a reactive value in shiny server function

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