Saving data into data frame from Shiny app

I am trying to save the data from the Shiny app to the data frame. Currently I do it locally with the hope that I can do it remotely later. However I have troubles even saving it locally. It does not save and then periodically RStudio asks me to terminate my R session after I quit my app. I got the code to work a couple of days ago, but now it is stuck.

I was following this example with slight modifications:

• I don't need to load the data frame in the app, so I removed output$responses. But even if I add it back, the code still doesn't work.
• I would like to load up the last entry if that exists, so I added observeEvent(input$load....

I do not have any errors. So I'm not sure what is going on.

My code:

library(shiny)

# Define the fields we want to save from the form
fields <- c("name", "used_shiny", "r_num_years")

default_name <- ""
default_used <- FALSE
default_years <- 2


saveData <- function(data) {
  data <- as.data.frame(t(data))
  if (exists("responses")) {
    responses <- rbind(responses, data)
  } else {
    responses <- data
  }
}



ui = fluidPage(
    #DT::dataTableOutput("responses", width = 300), tags$hr(),
    textInput("name", "Name", default_name),
    checkboxInput("used_shiny", "I've built a Shiny app in R before", default_used),
    sliderInput("r_num_years", "Number of years using R",
                0, 25, default_years, ticks = FALSE),
    actionButton("submit", "Submit"), 
    actionButton("load", "Load")
  )
  
server = function(input, output, session) {
    
    # Whenever a field is filled, aggregate all form data
    formData <- reactive({
      data <- sapply(fields, function(x) input[[x]])
      data
    })
    
    # When the Submit button is clicked, save the form data
    observeEvent(input$submit, {
      saveData(formData())
    })
    
    
    observeEvent(input$load, {
      if (exists("responses")){
        updateTextInput(session, "name", value = responses[nrow(responses), "name"])
        updateCheckboxInput(session, "used_shiny", value = responses[nrow(responses) ,"used_shiny"])
        updateSliderInput(session, "r_num_years", value = responses[nrow(responses) ,"r_num_years"])
      }
    })     
  }


# Run the application 
shinyApp(ui = ui, server = server)

I tried:

• creating the responses data.frame manually
• restarting RStudio in case of a glitch It didn't help.

I expect the code to save the input data into data.frame responses.