Warning: Error in [[<-.data.frame: replacement has 1 row, data has 0 - r

Question

My objective is to plot some graphs based on the data uploaded by users. Users can select how it is plotted. It works but there are warnings showing in the console. I think the issue lies with how the server module looks up values in the UI module but the UI module is not yet initalised. How can I get rid of the warnings? Thanks
Sample data:
fwrite(data.table(
age.band = c("45-54","55-64","55-64","55-64","55-64","45-54","35-44","25-34"),
gender = c("MALE","FEMALE","FEMALE","FEMALE","FEMALE","FEMALE","MALE","FEMALE"),
event = c("13/04/2022","8/04/2022","20/05/2021","12/02/2022","19/02/2021","19/03/2022","16/03/2021","19/03/2021"),
cause = c('Cancer','Cancer','Cancer','Mental Illness','Cancer','Musculoskeletal','Mental Illness','Musculoskeletal'),
type= c('Type1','Type1','Type1','Type2','Type2','Type2','Type2','Type2'),
rate = rep(1,8),
status = rep("accepted",8)
),"sample.csv",row.names=F)
Here is my code:
### UI and server to load data
loadDataUI <- function(id,label = "Upload",buttonLabel = "Browse") {
ns <- NS(id)
tagList(
fileInput(ns("file"),label=label,buttonLabel=buttonLabel,accept = c('.csv'),placeholder = "No file selected")
)
}
loadData <- function(id) {
moduleServer(
id,
function(input, output, session) {
userFile <- reactive({
shiny::validate(need(input$file, message = FALSE))
input$file
})
dt <- reactive({fread(userFile()$datapath)})
return(dt)
}
)
}
### UI and server to plot data
edaUI <- function(id,cat.option) {
ns <- NS(id)
tagList(
box(
dropdown(
selectInput(inputId = ns('category'),
label = 'Category',
choices = cat.option,selected = "all"),
dateRangeInput(ns("eventdaterange"), "Loss date range",
start = Sys.Date()-10,
end = Sys.Date()+10)
),
highchartOutput(ns("hc_init"))
)
)
}
eda <- function(id,filtered.data,measure){
moduleServer(
id,
function(input, output, session) {
observeEvent(filtered.data(), {
updateDateRangeInput(session,"eventdaterange",
start = min(filtered.data()$event),
end = max(filtered.data()$event))
})
output$hc_init <- renderHighchart({
tmp <- filtered.data() %>%
filter(event >= input$eventdaterange[1],event <= input$eventdaterange[2]) %>%
mutate(event.date = as.character(as.yearqtr(event)))
if (input$category == "all") {
tmp %>% group_by(event.date) %>%
summarise(measure=sum(!!sym(measure))) %>%
hchart("line", hcaes(x = event.date, y = measure)) %>%
hc_title(text="Chart")
} else {
tmp %>%
group_by(cat = !!sym(input$category),event.date) %>%
summarise(measure=sum(!!sym(measure))) %>% ungroup() %>%
arrange(cat,event.date) %>%
hchart("line", hcaes(x = event.date, y = measure,group = cat)) %>%
hc_title(text="Chart")
}
})
}
)
}
### Main UI and server
ui <- function() {
fluidPage(useShinydashboard(),
navbarPage(
tabPanel(
title = "Data analysis",
sidebarLayout(
sidebarPanel(
width = 2,
loadDataUI("input","","Upload data"),
awesomeRadio(
inputId = "benefit",
label = strong("Select type"),
choices = c("Type1", "Type2"),
selected = NULL,inline = TRUE,checkbox = FALSE)
),
mainPanel(
width = 10,edaUI("dt1",cat.option=c("all","age.band","gender"))
)
)
)
)
)
}
server <- function(input, output, session) {
data <- loadData("input")
filtered_data <- reactive({
date.cols <- c("event")
data()[type == input$benefit][,(date.cols):= lapply(.SD, dmy),.SDcols = date.cols]
})
eda("dt1",filtered_data,measure="rate")
}
shinyApp(ui = ui, server = server)