"Exciting" new features in Shiny 1.0.1

shiny-1.0.1-new-features.R

# ----------------------------------------------------------------- # 
# ------------- "Exciting" new features in Shiny 1.0.1 ------------ #
# ----------------------------------------------------------------- # 

library(shiny)

# 1. ----------------------------------------------- #
# ------------------ reactiveVal() ----------------- #
# -------------------------------------------------- #
ui <- fluidPage(
  actionButton("minus", "-1"),
  actionButton("plus", "+1"),
  br(),
  textOutput("value")
)

# The comments below show the equivalent logic using reactiveValues()
server <- function(input, output, session) {
  value <- reactiveVal(0)       # rv <- reactiveValues(value = 0)
  
  observeEvent(input$minus, {
    newValue <- value() - 1     # newValue <- rv$value - 1
    value(newValue)             # rv$value <- newValue
  })
  
  observeEvent(input$plus, {
    newValue <- value() + 1     # newValue <- rv$value + 1
    value(newValue)             # rv$value <- newValue
  })
  
  output$value <- renderText({
    value()                     # rv$value
  })
}
shinyApp(ui, server, options = list(launch.browser = rstudioapi::viewer))

# 2. ----------------------------------------------- #
# ---------- choiceNames and choiceValues ---------- #
# -- for radioButtons() and checkoboxGroupinput() -- #
# -------------------------------------------------- #
ui <- fluidPage(
  sidebarLayout(
    sidebarPanel( 
      radioButtons("normal", "Normal radio buttons:",
        c("Normal" = "norm", "Uniform" = "unif",
          "Log-normal" = "lnorm", "Exponential" = "exp")),
      hr(),
      radioButtons("fancy", "Fancy radio buttons:",
        choiceNames = list(tags$span(HTML("Normal &mu;<sub>1</sub>")),
          icon("calendar", "fa-3x"),
          icon("bed"),
          icon("cog", lib = "glyphicon"),
          img(src = "https://www.rstudio.com/wp-content/uploads/2016/09/RStudio-Logo-Blue-Gray-250.png")),
        choiceValues = c("html", "icon1", "icon2", "icon3", "img"))),
    mainPanel(textOutput("rb1"), textOutput("rb2"))
  )
)

server <- function(input, output, session) {
  output$rb1 <- renderText({
    paste("You chose", input$normal)
  })
  
  output$rb2 <- renderText({
    paste("You chose", input$fancy)
  })
}

shinyApp(ui, server, options = list(launch.browser = rstudioapi::viewer))