app.R

library(shiny)
library(coindeskr) #R-Package connecting to Coindesk API 
library(dygraphs)

last31 <- get_last31days_price() 

ui <- shinyUI(
  fluidPage(
  titlePanel('Bitcoin USD Price for Last 31 days'),
  mainPanel(
    h3('Minimum'),
    h3(htmlOutput('minprice')),
    h3('Maximum'),
    h3(htmlOutput('maxprice')),
    dygraphOutput("btcprice")
  )
))

server <- function(input,output){
  
  output$minprice <- renderText(
    paste('Price : $', min(last31), '<br>Date :', rownames(last31)[which.min(last31$Price)] )
  )
  
  
  output$maxprice <- renderText(
    paste('Price : $', max(last31), '<br>Date :', rownames(last31)[which.max(last31$Price)] )
  )
  output$btcprice <- renderDygraph(
    dygraph(data = last31, main = "Bitcoin USD Price for Last 31 days") %>% 
      dyHighlight(highlightCircleSize = 5, 
                  highlightSeriesBackgroundAlpha = 0.2,
                  hideOnMouseOut = FALSE, highlightSeriesOpts = list(strokeWidth = 3)) %>%
      dyRangeSelector()
  )
}

shinyApp(ui,server)