Make it shine

dev/dev.Rmd

@@ -455,3 +455,28 @@ tooltipOptions = list(
   formatTooltipY = htmlwidgets::JS("d => d + ' babies'")
 )
 ```
+
+## Shiny comes for free!
+
+Create a basic Shiny app with
+
+1. Slider input to pick number of values (1:26 letters)
+1. A new data button that generates new data of same dimension
+1. The data are reactive, `x = letters[1:n]`, `y = runif(n)`
+1. Use `frappeCharts::frappeChartOutput()` linked to `frappeCharts::renderFrappeChart()`
+    - bar plot
+    - fix `tooltipOptions` to turn the `runif()` into a percent.
+    
+`dev/shiny/app.R`
+
+Make a mistake in the spelling for `formatTooltipY`
+and demo how hard it is for the end user to track down what's wrong.
+This points to how important it is to do the validation on the R side
+or to do the extra work to make the R API friendly.
+
+It's also a good place to demo debug strategies for Shiny and regular widgets.
+Open the app in an external window,
+show the dev console,
+find the frappeCharts binding
+and add a breakpoint.
+Then reload and show how you an use the dev console there to figure things out.

dev/shiny/app.R

@@ -0,0 +1,39 @@
+library(shiny)
+
+ui <- fluidPage(
+  # Application title
+  titlePanel("htlmwidgets rock"),
+  sidebarLayout(
+    sidebarPanel(
+      # Sidebar with a button to create new data
+      sliderInput("n_bars", "Number of bars", 1, 26, 10),
+      actionButton("new_data", "New Data")
+    ),
+    # Show a plot of the generated distribution
+    mainPanel(
+      frappeCharts::frappeChartOutput("chart")
+    )
+  )
+)
+
+# Define server logic required to draw a histogram
+server <- function(input, output) {
+  data <- reactive({
+    input$new_data
+
+    data.frame(x = LETTERS[seq_len(input$n_bars)], Frequency = runif(input$n_bars))
+  })
+
+  output$chart <- frappeCharts::renderFrappeChart({
+    frappeCharts::frappeChart(
+      data(),
+      type = "bar",
+      tooltipOptions = list(
+        formatTooltipY = htmlwidgets::JS("d => Math.round(d * 100) + '%'")
+      )
+    )
+  })
+}
+
+# Run the application
+shinyApp(ui = ui, server = server)