Shiny check reactiveValue existence with validate -- Not Found - r

Question

I have a shiny code like in the below. I need to define variables as reactiveValues to be updatable (or I could define them I think as global but then I have to press clean objects from Rstudio which is not very user-friendly).I try to run a validate code to check for existence of the data I have defined as reactiveValues. validate(need(exists("GSEmRNA$d"),message="Dataframe not found")) yields "Dataframe not found" thus, does not plot my boxplot. If I define them as global variables and forget to press clean objects, code might mix up as old data can be passed as if it is new. Any help is appreciated.
server.R
shinyServer(function(input, output) {
observeEvent(input$GoButton,{
dataset <- data.frame(first= c(1,5,9),second=c(8,5,13), third=c(10,3,17))
GSEmRNA <- reactiveValues(d=dataset)
})
output$BoxplotDataset <- renderPlot({
if (input$GoButton== 0) {return()}
else{
validate(need(exists("GSEmRNA$d"),message="Dataframe not found"))
boxplot(GSEmRNA$d)}
})
})
ui.R
library(shiny)
shinyUI(pageWithSidebar(
headerPanel("Dataset Selection"),
sidebarPanel(
actionButton("GoButton","GO")
),
mainPanel(
wellPanel(
column(8, plotOutput("BoxplotDataset")
)
)
)))
FOR THE RECORD, I ALSO POSTED THIS QUESTION TO SHINY GOOGLE DISCUSS GROUP https://groups.google.com/forum/#!topic/shiny-discuss/ZV5F6Yy-kFg

Answer 1

Here are the updated code. The points are:
library(shiny)
server <-shinyServer(function(input, output) {
GSEmRNA <- reactiveValues(d=NULL) #define it ouside
observeEvent(input$GoButton,{
dataset <- data.frame(first= c(1,5,9),second=c(8,5,13), third=c(10,3,17))
GSEmRNA$d <- dataset #assign it inside
})
output$BoxplotDataset <- renderPlot({
validate(need(GSEmRNA$d,"Dataframe not found")) # changed as well
boxplot(GSEmRNA$d)
})
})
ui <- pageWithSidebar(
headerPanel("Dataset Selection"),
sidebarPanel(
actionButton("GoButton","GO")
),
mainPanel(
wellPanel(
column(8, plotOutput("BoxplotDataset")
)
)
))
runApp(list(ui=ui,server=server))
Defined the reactiveValues outside of the observeEvent
Changed the reactiveValues inside of the observeEvent
Changed the validate and need.