Shiny: Switching between reactive data sets with rhandsontable - r

Question

In the below toy example I have two data sets df1 and df2. The data sets are output to an interactive table using shiny & rhandsontable. My issue is that the output$out only recognizes the shift in data sets if the user hasn't edited the data set in the shiny application as indicated by is.null(input$out).
How do I fix the below code to load either df1 or df2 when input$df changes when input$out isn't null?
require(rhandsontable)
require(shiny)
df1 <- data.frame(col1 = rnorm(20),
col2 = rep(T, 20))
df2 <- data.frame(col1 = rnorm(20),
col2 = rep(F, 20))
funcX <- function(x) {
x$out <- ifelse(x$col2 == T, x$col1 * 1.5, x$col1)
x$out
}
df2$out <- funcX(df2)
df1$out <- funcX(df1)
server <- function(input, output) {
df <- reactive({
if (input$df == "df1") {
df <- df1
} else {
df <- df2
}
df
})
output$out <- renderRHandsontable({
if (is.null(input$out)) {
hot <- rhandsontable(df())
} else {
str(input$out)
hot <- hot_to_r(input$out)
hot$out <- funcX(hot)
hot <- rhandsontable(hot)
}
hot
})
}
ui <- fluidPage(sidebarLayout(sidebarPanel(
selectInput(
'df', 'Select data.frame:',
choices = c('df1', 'df2'),
selected = 'df1'
)
),
mainPanel(rHandsontableOutput("out"))))
shinyApp(ui = ui, server = server)

Answer 1

You could use reactiveValues to store the df1 and df2 data frames, and update these values when they are modified. Here's an example server.R code:
server <- function(input, output) {
values = reactiveValues()
values[["df1"]] <- df1
values[["df2"]] <- df2
observe({
if (!is.null(input$out)) {
temp <- hot_to_r(input$out)
temp$out <- funcX(temp)
if (isolate(input$df) == "df1") {
values[["df1"]] <- temp
} else {
values[["df2"]] <- temp
}
}
})
df <- reactive({
if (input$df == "df1") {
df <- values[["df1"]]
} else {
df <- values[["df2"]]
}
df
})
output$out <- renderRHandsontable({
hot <- rhandsontable(df())
hot
})
}
When the table is changed, the correct df1 or df2 is updated in the reactive values. In the observer, the input$df is isolated so that this part of the code only reacts to when the user changes the tables.