r shiny: updating rhandsontable from another rhandsontable

Question

I hope you're well. I am trying to create a shiny dashboard whereby a user is able to update one rhandsontable from another. My code is as follows:

library(shiny)
library(rhandsontable)

channel <- c("TV","Radio","Digital")
start.date <- as.Date("2017-01-01")
end.date <- as.Date("2017-01-07")
date.range <- as.POSIXct((seq(start.date,end.date,by="day")), origin = "1970-01-01")
date.range <- as.data.frame(date.range)
colnames(date.range) <- c("date")
date.range[channel] <- 0
table1 <- date.range
table2 <- date.range
#Define the tables.

ui <- fluidPage(
  br(),
  fluidRow(
    column(4, rHandsontableOutput("table1output")),
    column(4, rHandsontableOutput("table2output"))
  ))

server <- function(input,output,session){
  table <- reactiveValues()
  table$table1 <- table1
  table$table2 <- table2
  #define reactive values as table1 and table2

  output$table1output <- renderRHandsontable({rhandsontable(table$table1)})
  output$table2output <- renderRHandsontable({rhandsontable(table$table2)})
  #rhandsontable outputs

  observeEvent(input$table1output,{
    df <- hot_to_r(input$table1output)
    df <- as.data.frame(df)
    table$table2 <- df
  })
  #if a user updates table1 table2 should also update.

  observeEvent(input$table2output,{
    df <- hot_to_r(input$table2output)
    df <- as.data.frame(df)
    table$table1 <- df
  })
  #if a user updates table2 table1 should also update.

}

shinyApp(ui = ui, server = server)

Whenever I run the code i get the following errors:

Warning: Error in as: no method or default for coercing “character” to “NA” 

I can't for the life of me get this to work! Any help would be very much appreciated!

Cheers,

Harry

Answer 1

Allowed date formats in rhandsontable

The first problem is the format of the date column. It seems like POSIXct is not allowed here. According to the github documentation of rhandsontable, Date as in Sys.Date() is recommended. So replacing

date.range <- as.POSIXct((seq(start.date,end.date,by="day")), origin = "1970-01-01")

with

date.range <- as.Date((seq(start.date,end.date,by="day")), origin = "1970-01-01")

solves this issue. The warning

Warning: Error in as: no method or default for coercing “character” to “NA”

created by the call to hot_to_r should be gone now.

Updating both tables at once

In order to make all changes in table1 affect table2 and vice versa, you can use the same reactive value to store the tables on the server side.

Here is a full working solution.

library(shiny)
library(rhandsontable)

channel <- c("TV","Radio","Digital")
start.date <- as.Date("2017-01-01")
end.date <- as.Date("2017-01-07")
date.range <- as.Date((seq(start.date,end.date,by="day")), origin = "1970-01-01")
date.range <- as.data.frame(date.range)
colnames(date.range) <- c("date")
date.range[channel] <- 0
table1 <- date.range
table2 <- date.range
#Define the tables.

ui <- fluidPage(
  br(),
  fluidRow(
    column(4, rHandsontableOutput("table1output")),
    column(4, rHandsontableOutput("table2output"))
  ))

server <- function(input,output,session){
  table <- reactiveValues()
  table$table1 <- table1
  #DEFINE ONLY TABLE1

  output$table1output <- renderRHandsontable({rhandsontable(table$table1)})
  output$table2output <- renderRHandsontable({rhandsontable(table$table1)})
  #rhandsontable outputs

  observeEvent(input$table1output,{
    df <- hot_to_r(input$table1output)
    df <- as.data.frame(df)
    table$table1 <- df
  }, ignoreInit = TRUE, ignoreNULL = TRUE
  )
  #if a user updates table1 table2 should also update.

  observeEvent(input$table2output,{
    df <- hot_to_r(input$table2output)
    df <- as.data.frame(df)
    table$table1 <- df
  }, ignoreInit = TRUE, ignoreNULL = TRUE
  )
  #if a user updates table2 table1 should also update.

}

shinyApp(ui = ui, server = server)