In jbkunst/highcharter: A Wrapper for the 'Highcharts' Library

library(highcharter)
options(highcharter.theme = hc_theme_hcrt(tooltip = list(valueDecimals = 2)))

Drilldown is the concept of inspecting increasingly high resolution data through clicking on chart items like columns, points or pie slices.

Exmaple I: Gapminder data

library(dplyr)
library(forcats)
library(purrr)
library(stringr)

data(gapminder, package = "gapminder")

gapminder2007 <- gapminder |>
  filter(year == max(year)) |>
  select(-year) |>
  mutate(pop = pop/1e6) |>
  arrange(desc(pop))

gapminder_column <- gapminder2007 |>
  group_by(continent) |>
  summarise(
    lifeExp = weighted.mean(lifeExp, pop),
    gdpPercap = weighted.mean(gdpPercap, pop),
    pop = sum(pop)
  ) |>
  mutate_if(is.numeric, round) |>
  arrange(desc(pop)) |>
  mutate(continent = fct_inorder(continent))

gapminder_column

gapminder_drilldown <- gapminder2007 |>
  group_nest(continent) |>
  mutate(
    id = continent,
    type = "column",
    # in the drilldown we'll give the mapping via creating the columns
    data = map(data, mutate, name = country, y  = pop),
    data = map(data, list_parse)
  )

gapminder_drilldown

The data is ready. Now, in this example due the continents and countries have the sames values (pop, lifeExp, ...) we can use the same pointFormat for the tooltips:

x <- c("Population (MM)", "Life expectancy at birth", "GDP per capita (US$)")
y <- c("{point.pop}", "{point.lifeExp}", "$ {point.gdpPercap}")

tt <- tooltip_table(x, y)

hchart(
  gapminder_column,
  "column",
  hcaes(x = continent, y = pop, name = continent, drilldown = continent),
  name = "Population",
  colorByPoint = TRUE
) |>
  hc_drilldown(
    allowPointDrilldown = TRUE,
    series = list_parse(gapminder_drilldown)
  ) |>
  hc_tooltip(
    pointFormat = tt, # "{point.name} {point.pop}"
    useHTML = TRUE,
    valueDecimals = 0
  ) |>
  hc_yAxis(
    title = list(text = "Population in millions (log scale)"),
    type = "logarithmic",
    minorTickInterval = 'auto'
  ) |>
  hc_xAxis(
    title = ""
  )

Exmaple II: Pokémon data

Same recipe, different data. Just copy & pasting code:

pkmn_min <- pokemon |>
  count(type_1, color = type_1_color) |>
  mutate(type_1 = fct_reorder(type_1, .x = n)) |>
  arrange(desc(type_1))

pkmn_ddn <- pokemon |>
  count(type_1, type_2, color = type_mix_color) |>
  arrange(type_1, desc(n)) |>
  mutate(type_2 = ifelse(is.na(type_2), str_c("only ", type_1), type_2)) |>
  group_nest(type_1) |>
  mutate(
    id = type_1,
    type = "column",
    # in the drilldown we'll give the mapping via creating the columns
    data = map(data, mutate, name = type_2, y  = n),
    data = map(data, list_parse)
  )

hchart(
  pkmn_min,
  type = "column",
  hcaes(x = type_1, y = n, color = color, drilldown = type_1),
  name = "Pokémons"
  ) |>
  hc_drilldown(
    activeAxisLabelStyle = list(textDecoration = "none"),
    allowPointDrilldown = TRUE,
    series = list_parse(pkmn_ddn)
  ) |>
  hc_yAxis(
    title = list(text = ""),
    endOnTick = FALSE,
    opposite = TRUE
    ) |>
  hc_xAxis(
    title = list(text = ""),
    endOnTick = FALSE,
    gridLineWidth = 0,
    tickWidth = 0
    ) |>
  hc_chart(
    style = list(fontFamily = "Gloria Hallelujah")
  )

Example III: Custom tooltips and colors

(Example thanks to Claire).

dtrees <- tibble(
  tree = c("A", "B"),
  apples = c(5, 7),
  species = c("Fuji", "Gala"),
  trunk_size = c(30, 40)
  ) |> 
  # rowise is used to avoid vectorization in tags$td, ie, do it row by row
  rowwise() |> 
  mutate(
    tooltip_text = list(
      tags$table(
        tags$tr(tags$th("Tree"), tags$td(tree)),
        tags$tr(tags$th("# Apples"), tags$td(apples))
      )
    )
  ) |> 
  ungroup() |> 
  mutate(
    tooltip_text = map_chr(tooltip_text, as.character),
    # clean text
    tooltip_text = str_trim(str_squish(tooltip_text))
    )

dflowers <- tibble(
  tree = c(rep("A", 3), rep("B", 4)),
  rose = c("R1", "R2", "R3", "R4", "R5", "R6", "R7"),
  petals = c(10, 13, 15, 20, 24, 26, 27),
  color = c(
    "gray",
    "#FFB6C1",
    "#8B0000",
    "purple",
    "#FF10F0",
    "#ffffbf",
    "red"
  ),
  price = c(3, 2, 4, 3.5, 5, 2.5, 4.5)
  ) |>   
  rowwise() |> 
  mutate(
    tooltip_text = list(
      tags$table(
        tags$tr(tags$th("Flower"), tags$td(rose)),
        tags$tr(tags$th("# Petals"), tags$td(petals)),
        tags$tr(tags$th("Price"), tags$td(str_c("$ ", price)))
      )
    )  
  ) |> 
  ungroup() |> 
  mutate(
    tooltip_text = map_chr(tooltip_text, as.character),
    # clean text
    tooltip_text = str_trim(str_squish(tooltip_text))
  )

dflowers_dd <- dflowers |>
  group_nest(id = tree) |>
  mutate(
    type = "column",
    data = map(data, mutate, name = rose, y = petals),
    data = map(data, list_parse),
    name = "Petals"
  )

hchart(
  dtrees,
  "column",
  hcaes(tree, apples, drilldown = tree),
  name = "Apples",
  colorByPoint = TRUE
) |>
  hc_drilldown(
    breadcrumbs = list(
      format = 'back to {level.name} series',
      # enabled = FALSE,
      showFullPath = FALSE
      ),
    allowPointDrilldown = TRUE,
    series = list_parse(dflowers_dd)
    ) |>
  hc_yAxis(title = list(text  = "")) |>
  hc_xAxis(title = list(text  = "")) |>
  hc_tooltip(
    headerFormat = "", # remove header
    pointFormat = "{point.tooltip_text}",
    useHTML = TRUE
    )