Order of repeated Shiny Modules using lapply and insertUI - r

Question

I created a (for demonstration purposes reproducible) shiny app where the ui creates some Data (DataPack) (a list with two elements) by clicking the "Load"-button. Every element of this list is plotted via the module using lapply in the server function.
The app works, however, the plots come out in reverse order (DataPack$two with rnorm(n)^2 before DataPack$one with rnorm(n)) but are expected to be shown as called (lapply(names(DataPack()), function(DataSetName) {...})). How do I fix this/repeat calling modules in an exactly given order and what is the explanation for that behavior?
library(shiny)
library(TTR)
Module_ui <- function(id) {
ns <- shiny::NS(id)
shiny::uiOutput(ns("Plot"))
}
Module_Server <- function(
input, output, session,
DataPack, DataSetName, InputButton_GetData, xlim) {
AnalysedPack <- eventReactive(c(
InputButton_GetData(),
input$InputButton_ProcessData), {
message(paste("Analysed Pack", DataSetName))
AnalysedPack <-
runMean(DataPack()[[DataSetName]],
min(input$NumericInput_BW,
length(DataPack()[[DataSetName]])))
return(AnalysedPack)
})
output[['Plot']] <- renderUI({
ns <- session$ns
tags$div(
id = environment(ns)[['namespace']],
tagList(
fluidRow(
column(2, column(12, fluidRow(
numericInput(
inputId = ns("NumericInput_BW"),
label = NULL,
min = 1,
max = 100,
value = 10,
step = 1))),
fluidRow(
column(12, actionButton(
ns("InputButton_ProcessData"),
"Process", width = "100%")))),
column(10,
renderPlot({
message(paste("Base_Plot", DataSetName))
plot(DataPack()[[DataSetName]],
xlim = c(xlim()[1],
xlim()[2]))
lines(AnalysedPack(),
col = "tomato", lwd = 2)
}) ) )
)
)
})
}
ui <- fluidPage(
fluidRow(
column(
6,
column(
12,
fluidRow(h4("Data Generation")),
fluidRow(actionButton(
"InputButton_GetData", "Load", width = "100%")))),
column(
6,
column(
12,
fluidRow(h4("Update Plot")),
sliderInput(
"SliderInput_xAxis",
label = NULL,
min = 0,
max = 150,
value = c(0, 150),
animate = TRUE)
)
),
column(12, actionButton('addButton', '', icon = icon('plus')))
)
)
server <- function(input, output, session) {
DataPack <- eventReactive(
input$InputButton_GetData, {
message("DataPack")
n <- round(runif(1, min = 100, max = 500))
message(n)
DataPack <- NULL
DataPack$one <- rnorm(n)
DataPack$two <- rnorm(n)^2
updateSliderInput(
session = session,
inputId = "SliderInput_xAxis",
value = c(1, n),
min = 1,
max = n)
return(DataPack)
})
SliderInput_xAxis_rx <-
reactive(input$SliderInput_xAxis)
InputButton_GetData_rx <-
reactive(input$InputButton_GetData)
observeEvent(input$InputButton_GetData, {
lapply(names(DataPack()), function(DataSetName) {
id <- sprintf('Plot%s', DataSetName)
insertUI(
selector = "#addButton",
where = "afterEnd",
ui = Module_ui(id)
)
callModule(
Module_Server, id,
DataPack = DataPack,
DataSetName = DataSetName,
InputButton_GetData = InputButton_GetData_rx,
xlim = SliderInput_xAxis_rx)
})
})
}
shinyApp(ui, server)

Answer 1

This code:
insertUI(
selector = "#addButton",
where = "afterEnd",
ui = Module_ui(id)
)
inserts the UI after the element #addButton. So the first call generates, schematically:
#addButton
ui1
And the second call, as the first one, inserts after #addButton, not after ui1:
#addButton
ui2
ui1
So, reverse the names.