R Shiny: remove newly created tabs - r

Question

I'm writing a shiny app in which I want the user to be able to add and remove tabs. I know how to add tabs if the user clicks on a tab specifically made for that (thanks to the answer here) but I can't figure out how to remove the lastly created tab.
Here's a reproducible example:
library(shiny)
library(shinyWidgets)
ui <- navbarPage(position = "static-top",
title = "foo",
id = "tabs",
tabPanel(title = "Name 1",
fluidRow()),
tabPanel(title = "More",
icon = icon("plus"),
fluidRow()),
tabPanel(title = "Less",
icon = icon("minus"),
fluidRow())
)
server <- function(input, output) {
count <- reactiveVal(1)
observeEvent(input$tabs, {
if (input$tabs == "More"){
count(count()+1)
id = paste0("Name ", count())
insertTab(inputId = "tabs",
tabPanel(title = id,
fluidRow(column(
width = 12))
), target = "More", position = "before",
select = TRUE)}
if (input$tabs == "Less"){
count(count()+1)
id = paste0("Name ", count())
removeTab(inputId = "tabs",
target = id
)}
})
}
shinyApp(ui = ui, server = server)
Here, you can see that clicking on the tab More adds a tab named Name i with i the number of clicks made on the tab More. However, clicking on the tab Less does nothing.
What I would like is the following:
if the user clicks at least once on More, then clicking on Less removes the last created tab (therefore placed before More)
if the user does not click on More then clicking on Less does nothing
imagine that I click twice on More then there will be two additional tabs named Name 2 and Name 3. Clicking on Less will remove Name 3 but if I click again on More, the additional tab will be again called Name 3 (therefore clicking on Less should not prevent the re-use of the name of the tab removed).
Does anybody know how to do it?

Answer 1

I've done this with adding selectors and having a button remove then reuse the selector indices. To do this using reactive values that count each time the individual button is pressed or logging when an interaction is done.
Give the below code a try:
library(shiny)
library(shinyWidgets)
ui <- navbarPage(position = "static-top",
title = "foo",
id = "tabs",
tabPanel(title = "Name 1",
fluidRow()),
tabPanel(title = "More",
icon = icon("plus"),
fluidRow()),
tabPanel(title = "Less",
icon = icon("minus"),
fluidRow())
)
server <- function(input, output) {
count <- reactiveValues(value = 1)
observeEvent(input$tabs, {
if (input$tabs == "More"){
count$value <- count$value + 1
id = paste0("Name ", count$value)
insertTab(inputId = "tabs",
tabPanel(title = id,
fluidRow(column(
width = 12))
), target = "More", position = "before",
select = TRUE)}
if (input$tabs == "Less"){
print(count$value)
id = paste0("Name ", count$value)
removeTab(inputId = "tabs",
target = id
)
count$value <- count$value -1
}
})
}
shinyApp(ui = ui, server = server)