tibble slice function error in a R Shiny app

Question

I am trying to make a RShiny app to visualize a time series app. The app also allows the user to set/change a range of dates, this range will then update the Leaflet map points accordingly. In order to define the range on line 140 under sliderInput, I am using the slice function to get the slider range (initially rows 1:3) from a tibble. But I am getting an error while setting the range which as follows :

How can I slice an initial range (that the user can then change) from a tibble to create a double slider (range) sliderInput?

Warning: Error in : `slice()` expressions should return indices (positive or negative integers).

Code

# This is a Shiny time series map web application
library(shiny)
library(tidyverse)
library(tidyr)
library(leaflet)
library(xts)

# Create an xts to tibble function to get the maximum and
# minimum dates using slice_min and slice_max with pull
xts_to_tibble = function(xts_obj){
    data.frame(index(xts_obj), coredata(xts_obj)) %>% 
        set_names(c("date", names(xts_obj))) %>% 
        as_tibble()
}
dft = xts_to_tibble(df)
# Create sample data
Date = c("2014-04-08", "2014-06-04", "2014-04-30",
              "2014-05-30", "2014-05-01")
lat = as.numeric(c("45.53814", "45.51076", "45.43560", "45.54332",
        "45.52234"))
lon = as.numeric(c("-73.63672", "-73.61029", "-73.60100",
        "-73.56000 ", "-73.59022"))
id = as.numeric(c("1", "2", "3", "4", "5"))

# Create a df from the above columns
df = data.frame(id, lat, lon, Date)
df$Year = lubridate::year(df$Date)
df$Month = lubridate::month(df$Date, label = TRUE, abbr=FALSE)
df$Week = lubridate::week(df$Date)
df$Date = as.Date(df$Date)


ui = fluidPage(
    
    htmltools::htmlDependencies(icon("", verify_fa = FALSE)),
    tags$style(
        '
        .plot-zoom {
            position: absolute;
            border: none;
            background-color: transparent;
            bottom: 0;
            left: 0;
            z-index: 1;
        }
        .full-screen {
            position: fixed;
            height: 100vh !important;
            width: 100vw !important;
            left: 0;
            top: 0;
            z-index: 9999;
            overflow: hidden;
        }
        
        .leaflet-full-screen {
            position: relative;
        }
        '
    ),
    
    # Title
    titlePanel("Time Series Visiualization Map"),

    sidebarLayout(
        
        # Define the sidebar
        sidebarPanel(
            
            radioButtons(inputId = "Frequency",
                         label = " Select Time Series Frequency",
                         choices = c("weeks",
                                     "months",
                                     "years"),
                         selected = "weeks",
                         inline = T),
            
            uiOutput("Time_Series_UI")
            ),
        mainPanel(
            div(
                class = "leaflet-full-screen",
                leafletOutput("Time_Series_Map"))),
    ),
    tags$script(HTML(
        "
        function plotZoom(el){
            el = $(el);
            var parent = el.parent().parent();
            if(el.attr('data-full_screen') === 'false') {
                parent.addClass('full-screen')
                      .css('position', '')
                      .trigger('resize').fadeOut().fadeIn();
                el.attr('data-full_screen', 'true');
            } else {
                parent.removeClass('full-screen')
                      .css('position', 'relative')
                      .trigger('resize').fadeOut().fadeIn();
                el.attr('data-full_screen', 'false');
            }
        }
        
        $(function(){
           $('.leaflet-full-screen  .leaflet.html-widget').append(
            `
            <div class='plot-zoom'>
                <button onclick=plotZoom(this)  data-full_screen='false' title='Full screen'>
                    <i class='fa fa-expand-arrows-alt'></i>
                </button>
            </div>
            `); 
        })
        "
    ))
    )
    


# Define server logic required 
server = function(input, output) {
    
    # Render slider input depending on data frequency
    
    observe({
        # Create an xts object
        df_xts = xts(df, order.by = as.Date(df$Date))
        
        #All_Dates = unique(df$Start_Date)
        
        Filtered_Dates = df_xts[xts::endpoints(
            df_xts,
            on = input$Frequency
            )] %>% xts_to_tibble()
    
    output$Time_Series_UI = renderUI({
        sliderInput("Date", "Date:",
                    min = pull(slice_min(Filtered_Dates, date),date),
                    max = pull(slice_max(Filtered_Dates, date),date),
                    value = Filtered_Dates[1:3,][[1]],
                    step = 1,
                    #timeFormat = "%YYYY-%MM-%DD",
                    animate = T)
    })
    
    })
    
    # Filter data for the date selected
    Filtered_Data = reactive({
        return(subset(df, (Week >= input$Date[1] && month <= input$Date[2])))
    })
        
    # Filtered_Data = reactive({
    #     req(input$Date)
    #     filter(df, Date == input$Date)
    # })
        
    
    # Create the leaflet map
    output$Time_Series_Map = renderLeaflet({
        leaflet(df) %>% 
            addTiles() %>% 
            setView(lat = 0, lng = 0, zoom = 2) 
    })
    
    # Create data markers for selected date
    observe({
        
        leafletProxy("Time_Series_Map", data = Filtered_Data()) %>%
            addCircleMarkers(lng = ~lon, lat = ~lat, 
                             popup = ~id)
    })     
    
}

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

Update

I did try using this answer but I am still getting the same error.