Insert warning message from selectInput option - r

Question

Friends, could you help me to insert a warning message if an option is selected in selecInput. In my case, I would like it to be the case if the option "Exclude farms" is selected, a message like: Change filter options selected above. The executable code is below:
library(shinyBS)
library(shiny)
popoverTempate <-
'<div class="popover popover-lg" role="tooltip"><div class="arrow"></div><h3 class="popover-title"></h3><div class="popover-content"></div></div>'
DES_filter1<-paste(".........", sep = "<br>")
ui <- fluidPage(
tags$head(
tags$style(HTML(".popover.popover-lg {width: 500px; max-width: 500px;}"))
),
titlePanel("Old Faithful Geyser Data"),
sidebarLayout(
sidebarPanel(
radioButtons(
"filter1",
h3("Select properties"),
choiceValues = c(1, 2),
choiceNames = list(
tagList(
tags$span("All properties"),
tags$span(icon("info-circle"), id = "icon1", style = "color: blue;")
),
tagList(
tags$span("Exclude properties"),
tags$span(icon("info-circle"), id = "icon2", style = "color: blue;")
)
),
selected = 1
),
bsPopover("icon1", "TITLE1", DES_filter1, placement = "right",
options = list(template = popoverTempate)),
bsPopover("icon2", "TITLE2", "CONTENT2", placement = "right"),
selectInput("filter2", h3("Select farms"),
choices = list("All farms" = 1,
"Exclude farms" = 2),
selected = 1),
),
mainPanel(
)
)
)
server <- function(input, output) {
}
shinyApp(ui = ui, server = server)

Answer 1

If you are open to using another package here is a shinyWidgets solution with a 'sendSweetAlert':
library(shinyWidgets)
library(shiny)
ui <- fluidPage(
titlePanel("Old Faithful Geyser Data"),
sidebarLayout(
sidebarPanel(
radioButtons(
"filter1",
h3("Select properties"),
choiceValues = c(1, 2),
choiceNames = list(
tagList(
tags$span("All properties"),
tags$span(icon("info-circle"), id = "icon1", style = "color: blue;")
),
tagList(
tags$span("Exclude properties"),
tags$span(icon("info-circle"), id = "icon2", style = "color: blue;")
)
),
selected = 1
),
selectInput("filter2", h3("Select farms"),
choices = list("All farms" = 1,
"Exclude farms" = 2),
selected = 1),
),
mainPanel(
)
)
)
server <- function(input, output, session) {
observe({
if(input$filter2 == 2){
sendSweetAlert(
session = session,
title = "Warning!",
text = "Change filter options selected above",
type = "warning"
)
}
})
}
shinyApp(ui = ui, server = server)
All is needed is to observe the selectInput value and when the input is on "Exclude farms" which has a value of 2 a warning message is sent.