R shiny - stop() in eventReactive without error message in console - r

Question

I just new in Shiny, and i have problem. i have a event reactive and the stop function inside. when I run my code(no checkbox and do click button), the shiny is work well. but in console display the error message "eventReactiveHandler". do you have a solution for my problem? i want to no error message in my console.
and i not expect the solution is
opt <- options(show.error.messages=FALSE)
on.exit(options(opt))
because the error will not display in my all code, i want just specifically in this error.
thank you... this is the code...
rm(list = ls())
library(shiny)
library(shinyBS)
var.x<-reactiveValues()
shinyApp(
ui =
fluidPage(
sidebarLayout(
sidebarPanel(
checkboxGroupInput("indepvar","Independent Variable",
choices = c("1"=1,"2"=2)),
actionButton("tabBut", "View Table")
),
mainPanel(
uiOutput("coba"),
uiOutput("popup4")
)
)
),
server =
function(input, output, session) {
output$coba <- renderUI({
gendata()
indep<-NULL
for(i in 1:length(var.x)){
indep <- paste(indep,var.x[i],",")
}
list(
renderText(indep)
)
})
gendata<- eventReactive(input$tabBut,{
if(is.null(input$indepvar)){
stop()
}
var.x<<- input$indepvar
})
output$popup4 <- renderUI({
if(!is.null(input$indepvar))return()
list(
bsModal("modalExample4", "Peringatan", "tabBut", size = "small",wellPanel(
"Anda belum memilih independent variabel..."
))
)
})
}
)

Answer 1

I wouldn't advise suppressing error messages, as there are in there for you, I suggest you look into validate and need in shiny, you can go read validation article
To quickfix you issue you can just return NULL
rm(list = ls())
library(shiny)
library(shinyBS)
var.x<-reactiveValues()
shinyApp(
ui =
fluidPage(
sidebarLayout(
sidebarPanel(
checkboxGroupInput("indepvar","Independent Variable",
choices = c("1"=1,"2"=2)),
actionButton("tabBut", "View Table")
),
mainPanel(
uiOutput("coba")
)
)
),
server =
function(input, output, session) {
output$coba <- renderUI({
gendata()
indep<-NULL
for(i in 1:length(var.x)){
indep <- paste(indep,var.x[i],",")
}
list(
renderText(indep)
)
})
gendata<- eventReactive(input$tabBut,{
if(is.null(input$indepvar)){
var.x <<- NULL
return(NULL)
stop()
}
var.x<<- input$indepvar
})
}
)

Answer 2

You need to do two things as per the code below:
Make sure that gendata returns nothing when there are no independent variables selected (see lines 37-40). This stops your original error message
Make sure that output$coba is not evaluated when gendata has no value (see line 25)
Hope this helps,
John
rm(list = ls())
library(shiny)
library(shinyBS)
var.x<-reactiveValues()
shinyApp(
ui =
fluidPage(
sidebarLayout(
sidebarPanel(
checkboxGroupInput("indepvar","Independent Variable",
choices = c("1"=1,"2"=2)),
actionButton("tabBut", "View Table")
),
mainPanel(
uiOutput("coba"),
uiOutput("popup4")
)
)
),
server =
function(input, output, session) {
output$coba <- renderUI({
req(gendata())
indep<-NULL
for(i in 1:length(var.x)){
indep <- paste(indep,var.x[i],",")
}
list(
renderText(indep)
)
})
gendata<- eventReactive(input$tabBut,{
if(is.null(input$indepvar)) {
var.x <<- NULL
return()
}
var.x<<- input$indepvar
})
output$popup4 <- renderUI({
if(!is.null(input$indepvar))return()
list(
bsModal("modalExample4", "Peringatan", "tabBut", size = "small",wellPanel(
"Anda belum memilih independent variabel..."
))
)
})
}
)