rCharts NVD3 Shiny App

server.R

require(rCharts)
shinyServer(function(input, output) {
  output$myChart <- renderChart({
    hair_eye = as.data.frame(HairEyeColor)
    p6 <- nPlot(Freq ~ Hair, group = 'Eye', data = subset(hair_eye, Sex == input$gender), 
      type = input$type, dom = 'myChart', width = 800)
    p6$chart(color = c('brown', 'blue', '#594c26', 'green'), stacked = input$stack)
    return(p6)
  })
})

ui.R

require(rCharts)
shinyUI(pageWithSidebar(
  headerPanel("rCharts: Interactive Charts from R | NVD3"),
  
  sidebarPanel(
    selectInput(inputId = "gender",
      label = "Choose Gender",
      choices = c("Male", "Female"),
      selected = "Male"),
    selectInput(inputId = "type",
      label = "Choose Chart Type",
      choices = c("multiBarChart", "multiBarHorizontalChart"),
      selected = "multiBarChart"),
    checkboxInput(inputId = "stack",
      label = strong("Stack Bars?"),
      value = FALSE)
  ),
  mainPanel(
    showOutput("myChart", "nvd3")
  )
))

I'm having trouble implementing a slightly different example where the nplot is a scatterplot that switches between two variables. The plot doesn't appear even if I remove the switch by replacing datasetInput() with Murder in server.R.

Any ideas on how I can make this work?

server.R

require(rCharts)

shinyServer(function(input, output) {   
  datasetInput <- reactive({
    switch(input$crime,
           "assault" = Assault,
           "murder"  = Murder)
  })
  output$arrestPlot <- renderChart({
    w2 <- nPlot(datasetInput() ~ UrbanPop, 
                data = USArrests, 
                type = 'scatterChart') 
    w2$chart(tooltipContent =   "#! function(key, x, y, e){ 
             return e.point.row.names
  } !#")
    w2$set(title = "Water Footprint vs. Protein: California")
    w2$xAxis(axisLabel = 'Protein (%)')
    w2$yAxis(axisLabel = "Water Footprint: California (L/100g)" )
    w2$chart(showControls = F)  ## turn off magnify.
    return(w2)
})
}

ui.R

require(rCharts)

shinyUI(pageWithSidebar(
  headerPanel("rCharts: Interactive Charts from R | NVD3"),

  sidebarPanel(
    selectInput(inputId = "crime",
                label = "Crime:",
                choices = c("assault","murder"),
                selected = "assault")
  ),
  mainPanel(
    showOutput("arrestPlot", "nvd3")
  )
))