Shiny widget does not pass values correctly to ggplot - r

Question

I have the shiny dashboard below in which I want to use a variable from my pickerInput() and create a plot. The issue is that if I use ,for example name or snID instead of input$DB the plot is created. But when I use input$DB I get: Warning: Error in table: all arguments must have the same length
library(shiny)
library(shinydashboard)
library(shinyWidgets)
library(ggplot2)
library(plotly)
ui <- dashboardPage(
header = dashboardHeader(title = "My dashboard"),
sidebar = dashboardSidebar(
uiOutput("dbs")
),
body = dashboardBody(
plotlyOutput("fn")
)
)
server <- function(input, output, session) {
sts<-c("Rev","Rev")
sID<-c("123","124")
snID<-c("23","34")
name<-c("s","d")
pe<-data.frame(sts,sID,snID,name)
output$dbs<-renderUI({
pickerInput("DB", "Select Database/s",
choices = c("name","snID"),
multiple = F,options = list(`actions-box` = TRUE),
selected = "name")
})
output$fn<-renderPlotly({
#2.2 MAKING A TABLE for public.exists
tbl<-table(pe[[input$DB]], pe$sts)
ggplotly(
ggplot(as.data.frame(tbl), aes(!!sym(input$DB), Freq, fill = sts))
)
})
}
shinyApp(ui, server)

Answer 1

I suspect your output$fn reactive is executing before input$DB has a value. Therefore, add
req(input$DB)
at the start of the reactive, and you should be OK.
In the absence of any demo input data, it's difficult to be definitive.