install.packages("daterangepicker")

# install.packages("remotes")
remotes::install_github("trafficonese/daterangepicker")

library(shiny)
library(daterangepicker)

## UI ##########################
ui <- fluidPage(
  daterangepicker(
    inputId = "daterange",
    label = "Pick a Date",
    start = Sys.Date() - 30, end = Sys.Date(),
    style = "width:100%; border-radius:4px",
    icon = icon("calendar")
  ),
  verbatimTextOutput("print"),
  actionButton("act", "Update Daterangepicker"),
)

## SERVER ##########################
server <- function(input, output, session) {
  output$print <- renderPrint({
    req(input$daterange)
    input$daterange
  })
  observeEvent(input$act, {
    updateDaterangepicker(session, "daterange",
                          start = Sys.Date(), 
                          end = Sys.Date() - 100)
  })
}

shinyApp(ui, server)