R Shiny: Error: `server` must be a function

This is the script I am trying to run, randomApp function is a wrapper for a simple shiny app. However, when I call randomApp() it throws me an error: Error: 'server' must be a function. It looks to me that the server is already a function so I have no idea why it gives me an error. Any ideas?

library(shiny)
randomUI <- function(id) {
    tagList(
        textOutput(NS(id, "val")),
        actionButton(NS(id, "go"), "Go!")
    )
}
randomServer <- function(id) {
    moduleServer(id, function(input, output, session) {
        rand <- eventReactive(input$go, sample(100, 1))
        output$val <- renderText(rand())
    })
}
randomApp <- function(){
    ui <- fluidPage(
        randomUI("random1"),
        randomUI("random2"),
        randomUI("random3")
    )
    
    server <- function(input, output, session) {
        randomServer("random1")
        randomServer("random2")
        randomServer("random3")
    }
    
    runApp(ui, server)
}
randomApp()

>Solution :

You are using the wrong function to launch your app. You should use shinyApp rather than runApp when specifying a UI and server function. Check the help pages to see the difference.