How to implement shinyStore when using a table generated by the rhandsontable R package?

Question

I'm trying to implement the "save" feature from the answer in post How to use the localStorage option for DT in R Shiny? into my table rendered with rhandsontable but it's not working. That post involves table package DT, whereas I'm using rhandsontable and need to stick with rhandsontable. By "save", I mean preserving the table with all its cumulative inputs/outputs from one session to the next, which the referred-to post does for DT table. I will need to implement the "clear" function from that post later, but first I want to see how "save" works, and what I'm doing wrong in my below attempt, before moving on to adapting the "clear" function.

Below code has comments # add... for functions I pulled in from the reference post.

How would I enable the save feature in this rhandsontable example?

I get the following error message: Error : Can't access reactive value 'hottable' outside of reactive consumer. Do you need to wrap inside reactive() or observer()?

Code:

# If not installed already, un-comment and run the below 3 lines to install shinyStore package:
# install.packages("devtools")
# library(devtools)
# install_github("trestletech/shinyStore")

library(rhandsontable)
library(shiny)
library(shinyStore)

myDF <- data.frame(x = c(1, 2, 3))

ui <- fluidPage(
  initStore("store", "shinyStore-ex1"), # add
  br(),
  fluidRow(
    column(6,
           actionButton('addCol','Add column'),
           actionButton("save", "Save", icon("save")), # add
           actionButton("clear", "Clear", icon("stop")) # add
    )
  ),
  br(),rHandsontableOutput('hottable')
)

server <- function(input, output, session) {
  EmptyTbl <- reactiveVal(myDF)
  
  rv <- reactiveValues(uiTable = hot_to_r(input$hottable)) # add
  
  observeEvent(input$hottable, {
    EmptyTbl(hot_to_r(input$hottable))
  })
  
  output$hottable <- renderRHandsontable({
    rhandsontable(EmptyTbl(),useTypes = FALSE)
  })
  
  observeEvent(input$addCol, {
    newCol <- data.frame(c(1, 2, 3))
    names(newCol) <- paste("Col", ncol(hot_to_r(input$hottable)) + 1)
    EmptyTbl(cbind(EmptyTbl(), newCol))
  })
  
  # add observeEvent() below:
  observeEvent(input$save,{
    updateStore(session,name = "uiTable",rv$uiTable)
  },ignoreInit = TRUE)
  
}

shinyApp(ui, server)

ismirsehregal · Accepted Answer · 2022-11-03T10:36:24.403

Please check the following:

# If not installed already, un-comment and run the below 3 lines to install shinyStore package:
# install.packages("devtools")
# library(devtools)
# install_github("trestletech/shinyStore")

library(rhandsontable)
library(shiny)
library(shinyStore)

myDF <- data.frame(x = c(1, 2, 3))

ui <- fluidPage(
  initStore("store", "shinyStore-ex1"),
  br(),
  fluidRow(column(
    6,
    actionButton('addCol', 'Add column'),
    actionButton("save", "Save", icon("save")),
    actionButton("clear", "Clear", icon("stop")) # add
  )),
  br(),
  rHandsontableOutput('hottable')
)

server <- function(input, output, session) {
  uiTable <- reactiveVal(myDF)
  
  output$hottable <- renderRHandsontable({
    rhandsontable(uiTable(), useTypes = FALSE)
  })

  observeEvent(input$hottable, {
    uiTable(hot_to_r(input$hottable))
  })
  
  observeEvent(input$addCol, {
    newCol <- data.frame(c(1, 2, 3))
    names(newCol) <-
      paste("Col", ncol(hot_to_r(input$hottable)) + 1)
    uiTable(cbind(uiTable(), newCol))
  })
  
  observeEvent(input$save, {
    updateStore(session, name = "uiTable", uiTable())
  }, ignoreInit = TRUE)
  
  observeEvent(input$clear, {
    # clear tracking table:
    uiTable(myDF)
    
    # clear shinyStore:
    updateStore(session, name = "uiTable", myDF)
  }, ignoreInit = TRUE)
  
  observeEvent(input$store$uiTable, {
    uiTable(as.data.frame(input$store$uiTable))
  })
}

shinyApp(ui, server)

PS: As an alternative approach we could use rhandsontable::set_data() in the same manner as DT::replaceData to avoid recreating the widget via renderRHandsontable if the underlying table was changed.

I'm going to print out your solution and my OP code, and compare them line by line to bolster my understanding, of where I went wrong. THANK YOU AGAIN! You are a treasure for the community. — Curious Jorge - user9788072, Nov 03 '22 at 16:41
@CuriousJorge-user9788072 - Thanks for your kind words and sorry for the missing explanation - I was in a hurry. Let me know if you need details. Cheers — ismirsehregal, Nov 03 '22 at 17:35

score 0 · Answer 2 · answered Nov 04 '22 at 08:42

Please defer to ismirsehregal's complete solution. The below addresses my mistakes in the OP code, starting with a working solution that doesn't involve the "clear" function and preserving some OP object names for comparison ease, and then a line-by-line comparison of the code highlighting my OP errors and explaining the corrections:

Working code:

myDF <- data.frame(x = c(1, 2, 3))

ui <- fluidPage(
  initStore("store", "shinyStore-ex1"), # add
  br(),
  fluidRow(
    column(6,
           actionButton('addCol','Add column'),
           actionButton("save", "Save", icon("save")), # add
           actionButton("clear", "Clear", icon("stop")) # add
    )
  ),
  br(),rHandsontableOutput('hottable')
)

server <- function(input, output, session) {
  EmptyTbl <- reactiveVal(myDF)
  
  observeEvent(input$hottable, {
    EmptyTbl(hot_to_r(input$hottable))
  })
  
  output$hottable <- renderRHandsontable({
    rhandsontable(EmptyTbl(),useTypes = FALSE)
  })
  
  observeEvent(input$addCol, {
    newCol <- data.frame(c(1, 2, 3))
    names(newCol) <- paste("Col", ncol(hot_to_r(input$hottable)) + 1)
    EmptyTbl(cbind(EmptyTbl(), newCol))
  })
  
  observeEvent(input$save,{
    updateStore(session,name = "EmptyTbl",EmptyTbl())
  },ignoreInit = TRUE)
  
  observeEvent(input$store$EmptyTbl,{
    EmptyTbl(as.data.frame(input$store$EmptyTbl))
  })
  
}

shinyApp(ui, server)

Errors highlighted and explained:

How to implement shinyStore when using a table generated by the rhandsontable R package?

2 Answers2

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