R Shiny how can i updateProgressBar inside a function?

Question

I'm new here, sorry for any mistakes.

I have the following code working:

library(shinydashboard)
library(shinyWidgets)

#### Header ####
header <- dashboardHeader()

#### Sidebar ####
sidebar <- dashboardSidebar()

#### Body ####
body <- dashboardBody(
  actionButton("go", label = "Go!"),
  # Loading Bar
  progressBar("progress", value=0, total=100, title="", display_pct = TRUE)
)

ui = dashboardPage(header, sidebar, body)

#### Server ####
server <- function(input, output, session){
  observeEvent(input$go,{
    for(i in 1:13){
      updateProgressBar(
        session = session,
        id = "progress",
        value = i,
        total = 13,
        title = paste("Progress ", i, "/", 13)
      )
      Sys.sleep(0.2)
    }
    }
  )
}

shinyApp(ui, server)

But now I need to update the progressBar by some code inside a function already defined (in a source code, in fact). As a test I defined:

test_func <- function(){
  for(i in 1:13){
    updateProgressBar(
      session = session,
      id = "progress",
      value = i,
      total = 13,
      title = paste("Progress ", i, "/", 13)
    )
    Sys.sleep(0.2)
  }
}

And edited the server to:

#### Server ####
server <- function(input, output, session){
  observeEvent(input$go,{
    test_func()
    }
  )
}

I get the following error: "object type closure is not subsettable"

How can I do it in the right way? Thanks in advance.

Answer 1

Your problem seems to be down to environments.

I get an error (different to yours) when I define test_func outside the server function. When I define it inside the server function, I get the expected behaviour. Can you source your external file inside the server function?

If not, pass session as an argument to test_func. When I did that, and defined test_func outside the server function, everything worked as expected.