Value boxes

This (short) article on value_box() assumes you’ve loaded the following packages:

library(bslib)
library(shiny)
library(bsicons)

Build a Box App

Want to explore all of the value_box() options and layouts in an interactive app? Check out the Build a Box App! Use the app to quickly choose the right layout and theme for your value boxes, and then copy the code right into your own app.

Hello `value_box()`

A value_box() has 4 main parts:

value: Some text value.
title: Optional text to display above value.
showcase: Optional UI element(s) to display alongside the value.
theme: Optional theme to change the appearance of the value box.
...: Any other text/UI elements to appear below value.

As we’ll see later, one can be clever with what goes in the showcase, but in many cases an icon provides enough visual context for the box to feel “complete”. We recommend using the new bsicons package since it’s designed with Bootstrap in mind, but you could also use fontawesome or {icons}.

With each value box you can showcase a plot or an icon, choosing from one of three values for showcase_layout: "left center", "top right", or "bottom". See the Showcase Layouts section in the value_box() documentation for more details.

The overall appearance of the value box may be customized with the theme argument, where you can choose from a wide variety of themes — the Themes section of the value_box() documentation lays out all of your options.

value_box(
  title = "I got",
  value = "99 problems",
  showcase = bs_icon("music-note-beamed"),
  p("bslib ain't one", bs_icon("emoji-smile")),
  p("hit me", bs_icon("suit-spade"))
)

I got

99 problems

bslib ain't one

hit me

value_box(
  title = "I got",
  value = "99 problems",
  showcase = bs_icon("music-note-beamed"),
  showcase_layout = "top right",
  theme = "secondary",
  p("bslib ain't one", bs_icon("emoji-smile")),
  p("hit me", bs_icon("suit-spade"))
)

I got

99 problems

bslib ain't one

hit me

Dynamic rendering (Shiny)

When using Shiny to dynamically render value_box() contents, it’s good practice to use textOutput() to serve as a placeholder for value, title, etc. This way, if the value takes a moment to compute, the value box will appear before the value is ready, and thus reduces “layout shift” when the value is actually rendered.

ui <- page_fixed(
  value_box(
    title = "The current time",
    value = textOutput("time"),
    showcase = bs_icon("clock")
  )
)

server <- function(input, output) {
  output$time <- renderText({
    invalidateLater(1000)
    format(Sys.time())
  })
}

shinyApp(ui, server)

Multiple value boxes

To layout multiple value boxes, it’s recommended to use layout_column_wrap() (or layout_columns()), which ensures a uniform height and width (at least by default) across the boxes.

vbs <- list(
  value_box(
    title = "1st value",
    value = "123",
    showcase = bs_icon("bar-chart"),
    theme = "purple",
    p("The 1st detail")
  ),
  value_box(
    title = "2nd value",
    value = "456",
    showcase = bs_icon("graph-up"),
    theme = "teal",
    p("The 2nd detail"),
    p("The 3rd detail")
  ),
  value_box(
    title = "3rd value",
    value = "789",
    showcase = bs_icon("pie-chart"),
    theme = "pink",
    p("The 4th detail"),
    p("The 5th detail"),
    p("The 6th detail")
  )
)

layout_column_wrap(
  width = "250px",
  !!!vbs
)

1st value

123

The 1st detail

2nd value

456

The 2nd detail

The 3rd detail

3rd value

789

The 4th detail

The 5th detail

The 6th detail

And, when incorporating multiple value boxes into a larger filling layout, it’s good practice to set fill = FALSE on the layout container since that’ll prevent the boxes from using up more space than they really need. For example, try resizing the following example vertically. Notice how the height of the value boxes don’t change, but the height of the plot does (and it isn’t allowed to shrink below 200 pixels):

page_fillable(
  layout_column_wrap(
    width = "250px",
    fill = FALSE,
    vbs[[1]], vbs[[2]]
  ),
  card(
    min_height = 200,
    plotly::plot_ly(x = rnorm(100))
  )
)

Expandable sparklines

Under-the-hood, value_box() is implemented using card(), mainly to inherit it’s full_screen capabilities. Expanding a value_box() to full screen isn’t so useful when the showcase is something simple like an icon, but it becomes quite compelling for something like an “expandable sparkline”. The code to the right demonstrates one way you might go about that with plotly.

Note that, since this example is statically rendered (outside of Shiny), we make use of htmlwidgets::onRender() to add some JavaScript that effectively says: “Show the xaxis of the chart when it’s taller than 200 pixels; otherwise, hide it”.

Those of you who aren’t wanting to write JavaScript can achieve similar behavior (i.e., displaying a different chart depending on it’s size) via shiny::getCurrentOutputInfo(), as mentioned in the article on cards. In fact, here’s the source code for a Shiny app does effectively the same thing without any JavaScript (note how it also leverages other getCurrentOutputInfo() values to avoid hard coding "white" into the colors of the sparklines).

library(plotly)

sparkline <- plot_ly(economics) %>%
  add_lines(
    x = ~date, y = ~psavert,
    color = I("white"), span = I(1),
    fill = 'tozeroy', alpha = 0.2
  ) %>%
  layout(
    xaxis = list(visible = F, showgrid = F, title = ""),
    yaxis = list(visible = F, showgrid = F, title = ""),
    hovermode = "x",
    margin = list(t = 0, r = 0, l = 0, b = 0),
    font = list(color = "white"),
    paper_bgcolor = "transparent",
    plot_bgcolor = "transparent"
  ) %>%
  config(displayModeBar = F) %>%
  htmlwidgets::onRender(
    "function(el) {
      el.closest('.bslib-value-box')
        .addEventListener('bslib.card', function(ev) {
          Plotly.relayout(el, {'xaxis.visible': ev.detail.fullScreen});
        })
    }"
  )


value_box(
  title = "Personal Savings Rate",
  value = "7.6%",
  p("Started at 12.6%"),
  p("Averaged 8.6% over that period"),
  p("Peaked 17.3% in May 1975"),
  showcase = sparkline,
  full_screen = TRUE,
  theme = "success"
)

Personal Savings Rate

7.6%

Started at 12.6%

Averaged 8.6% over that period