actionButton and if condition - r

Question

So I have a complex shiny app with some internal default data. I added the possibility to update these internal data with new files (uploaded with fileInput()). I want that only after I click on a button, the default data and the new data merge together. I find this solution (just add any file in fileInput() to make it works).
library(shiny)
ui <- fluidPage(
fluidRow(
column(3, fileInput("fileupaziendedata", "Carica il file csv")), #just load any file
column(3, actionButton("mergeaziende", "Unisci"))), #the button that merges
hr(),
dataTableOutput("summary_table")
)
server <- function(input,output){
data = reactive({
data.frame(id = c(1:5), lett = c("A", "B", "C", "D", "E"))
})
datafromfile = reactive({
data.frame(id = c(6,7), lett = c("F", "G"))
})
data2 = reactive({
if(!is.null(input$fileupaziendedata) && input$mergeaziende > 0){
rbind(data(), datafromfile())
}else{
data()
}
})
output$summary_table <- renderDataTable({
data2()
})
}
shinyApp(ui=ui, server=server)
Now my problem is that since I used input$mergeaziende > 0 condition, after the first button press, it will be always greater than 0. Is there a way to prevent this?

Answer 1

I've seen this type of question come up before. Basically, how to "reset" the action button value. Here's my general solution. I reset a reactiveVal instead of trying to manipulate the input. Here the input will reset after 5, but it can be changed to something else (like when your data reactive triggers):
library(shiny)
ui <- fluidPage(
actionButton('click' ,'Click'),
textOutput('counter_out')
)
server <- function(session, input, output){
# initialize at - 0
# this is the value to observe (not input$click)
counter <- reactiveVal(0)
output$counter_out <- renderText(counter())
#increment per click
observeEvent(input$click, counter(counter() + 1))
observe({
#WHEN you want the count reset
if(counter() > 5) counter(0)
})
}
shinyApp(ui, server)