• use a framework (shiny)
• use widgets (htmlwidgets)
• seperation of concerns (ui, server, custom R functions)

3 files that live in the same folder

1. ui.R (Web Graphical user interface, looks good.)
2. server.R (backend, does the work)
3. global.R (globally available objects) (optional)

=> let's build our first app!

• create HTML/CSS/Javascript code
• start/run a (local) webserver
• communication between the R session and the browser

library(shiny)
shinyUI(fluidPage(
  titlePanel("A random normal"),
  # Sidebar with a slider input for number of bins 
  sidebarLayout(
    sidebarPanel(
       sliderInput("obs",
                   "Number of obs:",
                   min = 1,
                   max = 1000,
                   value = 100)
    ),
    mainPanel(
       plotOutput("randomPlot")
    )
  )
))

• Markup language
• content is wrapped in tags

<a href="http://somedestination.com">some link</a>
<b>this is bold</b>
<i>this is italic</i>
<div class="some-class">a class with a style</div>

=> shiny functions create these wraps for us.

shinyServer(function(input, output) {
    output$randomPlot <- renderPlot({
    hist(rnorm(input$obs),
         col = 'darkgray',
         border = 'white')
  })
})

• local
• shiny server
• SaaS

Take the official quiz by rstudio.com!

This course: dashboard structure

• sidebar
• topbar
• main panel
• menu buttons / sub pages

library(shinydashboard)
dashboardPage(
  dashboardHeader(),
  dashboardSidebar(),
  dashboardBody()
)

• Find items, e.g., sapa project
• organize items, demographics, analytics
• Which tools, widgets are needed?