Plots do not render when using geom_smooth()

[jvcasillas]

Whenever I add geom_smooth() to a ggplot the results do not render. Minimal working example:

library(shiny)
library(ggplot2)

# Define UI for app that draws a histogram ----
ui <- fluidPage(

  # App title ----
  titlePanel("Hello Shiny!"),

  # Sidebar layout with input and output definitions ----
  sidebarLayout(

    # Sidebar panel for inputs ----
    sidebarPanel(

      # Input: Slider for the number of bins ----
      sliderInput(inputId = "bins",
                  label = "Number of bins:",
                  min = 1,
                  max = 50,
                  value = 30)

    ),

    # Main panel for displaying outputs ----
    mainPanel(

      # Output: Histogram ----
      plotOutput(outputId = "distPlot")

    )
  )
)

# Define server logic required to draw a histogram ----
server <- function(input, output) {

  # Histogram of the Old Faithful Geyser Data ----
  # with requested number of bins
  # This expression that generates a histogram is wrapped in a call
  # to renderPlot to indicate that:
  #
  # 1. It is "reactive" and therefore should be automatically
  #    re-executed when inputs (input$bins) change
  # 2. Its output type is a plot
  output$distPlot <- renderPlot({

    x    <- faithful$waiting
    bins <- input$bins

    #hist(x, breaks = bins, col = "#75AADB", border = "white",
    #     xlab = "Waiting time to next eruption (in mins)",
    #     main = "Histogram of waiting times")

    dat <- data.frame(x = x)
    #ggplot(dat) + 
    #  aes(x = x) + 
    #  geom_histogram(bins = bins)
    ggplot(mtcars) + 
      aes(x = drat, y = mpg) + 
      geom_point() + 
      geom_smooth()
    
    })

}

# Create Shiny app ----
shinyApp(ui = ui, server = server)

If I remove the line with geom_smooth() the plot renders normally:

library(shiny)
library(ggplot2)

# Define UI for app that draws a histogram ----
ui <- fluidPage(

  # App title ----
  titlePanel("Hello Shiny!"),

  # Sidebar layout with input and output definitions ----
  sidebarLayout(

    # Sidebar panel for inputs ----
    sidebarPanel(

      # Input: Slider for the number of bins ----
      sliderInput(inputId = "bins",
                  label = "Number of bins:",
                  min = 1,
                  max = 50,
                  value = 30)

    ),

    # Main panel for displaying outputs ----
    mainPanel(

      # Output: Histogram ----
      plotOutput(outputId = "distPlot")

    )
  )
)

# Define server logic required to draw a histogram ----
server <- function(input, output) {

  # Histogram of the Old Faithful Geyser Data ----
  # with requested number of bins
  # This expression that generates a histogram is wrapped in a call
  # to renderPlot to indicate that:
  #
  # 1. It is "reactive" and therefore should be automatically
  #    re-executed when inputs (input$bins) change
  # 2. Its output type is a plot
  output$distPlot <- renderPlot({

    x    <- faithful$waiting
    bins <- input$bins

    #hist(x, breaks = bins, col = "#75AADB", border = "white",
    #     xlab = "Waiting time to next eruption (in mins)",
    #     main = "Histogram of waiting times")

    dat <- data.frame(x = x)
    #ggplot(dat) + 
    #  aes(x = x) + 
    #  geom_histogram(bins = bins)
    ggplot(mtcars) + 
      aes(x = drat, y = mpg) + 
      geom_point() 
    
    })

}

# Create Shiny app ----
shinyApp(ui = ui, server = server)