dataTableProxy to data.frame error in R Shiny - r

Question

I have created a demo app that allows the user to edit an existing df and then download the updated table as a .csv. The app runs almost fine, as when I click the download button, I get the following error:
Warning: Error in as.data.frame.default: cannot coerce class ‘"dataTableProxy"’ to a data.frame
[No stack trace available]
How can this be fixed?
Code
# Double click in a table cell to edit its value and then download the updated table
library(shiny)
library(DT)
library(tidyverse)
# Define UI for application that edits the table
ui = fluidPage(
DTOutput('x1'),
# App title
titlePanel("Downloading Data"),
# Sidebar layout with input and output definitions
sidebarLayout(
# Sidebar panel for inputs
sidebarPanel(
# Input: Choose dataset
selectInput("dataset", "Choose a dataset:",
choices = c("Demo Table")),
# Button
downloadButton("downloadData", "Download")
),
# Main panel for displaying outputs
mainPanel(
tableOutput("table")
)
))
# Define server logic required
server = function(input, output) {
x = iris
x$Date = Sys.time() + seq_len(nrow(x))
output$x1 = renderDT(x, selection = 'none', editable = TRUE)
proxy = dataTableProxy('x1')
observeEvent(input$x1_cell_edit, {
info = input$x1_cell_edit
str(info)
i = info$row
j = info$col
v = info$value
x[i, j] <<- DT::coerceValue(v, x[i, j])
replaceData(proxy, x, resetPaging = FALSE) # important
})
# Downloadable table (df) as csv
output$downloadData = downloadHandler(
filename = function() {
paste(input$dataset, ".csv", sep = "")
},
content = function(file) {
write.csv(proxy, file, row.names = FALSE)
}
)
}
# Run the application
shinyApp(ui = ui, server = server)

Answer 1

Replace
write.csv(proxy, file, row.names = FALSE)
with
write.csv(x, file, row.names = FALSE)

Answer 2

This is not a full answer!
I know where the error occurs and I can fix it. But I can not make the downloadhandler to download the datatable (instead an empty csv file is occuring).
This might be due to:
input$dataset is not defined in your code. Here is a similar post handling this issue:
Shiny App Upload and Download Data Dynamically Not Working
And I think more important as stated by Stephane Laurent in his answer:
Replace data in R formattable datatable using replaceData function
replaceData requires a dataframe in the second argument, not a datatable.
This is the reason you get the error.
When you have a datatable proxy, the dataframe is in proxy$x$data.
Using this code removes the error, but a blank .csv file is downloaded
# Downloadable table (df) as csv
output$downloadData = downloadHandler(
filename = function() {
paste(input$dataset, ".csv", sep = "")
},
content = function(file) {
write.csv(proxy$proxy, file, row.names = FALSE)
}
)
}