library(billboarder)
data("economics", package = "ggplot2")

With {billboarder} you can link tooltip between charts, i.e. when you hover over a graph, the tooltip will be displayed on all graphs linked with the same id.

Here a function to draw a line chart, the important part is bb_tooltip(linked = list(name = "my-tooltip")) at the end, it’s where we declare an ID to link charts. All charts with the name "my-tooltip" will be linked.

draw_line <- function(var, title, percent = TRUE) {
  billboarder(height = "280px") %>%
    bb_linechart(data = economics[, c("date", var)]) %>%
    bb_x_axis(tick = list(format = "%Y-%m", fit = FALSE)) %>%
    bb_y_axis(tick = list(format = if (percent) suffix("%"))) %>%
    bb_legend(show = FALSE) %>%
    bb_x_grid(show = TRUE) %>%
    bb_y_grid(show = TRUE) %>%
    bb_labs(title = title) %>%
    bb_tooltip(linked = list(name = "my-tooltip")) # <--- Id for linking tooltip
}

We can draw several line charts that will be linked to each other :

draw_line("psavert", "Personal savings rate", TRUE)
draw_line("uempmed", "Number of unemployed", TRUE)
draw_line("pce", "Personal consumption expenditures", FALSE)
draw_line("pop", "Total population", FALSE)

It also works in Shiny applications :

library(shiny)

ui <- fluidPage(
  fluidRow(
    column(
      width = 10, offset = 1,
      tags$h2("Linked tooltip in {billboarder}"),
      fluidRow(
        column(width = 6, billboarderOutput("g1")),
        column(width = 6, billboarderOutput("g2")),
        column(width = 6, billboarderOutput("g3")),
        column(width = 6, billboarderOutput("g4"))
      )
    )
  )
)

server <- function(input, output, session) {
  output$g1 <- renderBillboarder(
    draw_line("psavert", "Personal savings rate", TRUE)
  )
  output$g2 <- renderBillboarder(
    draw_line("uempmed", "Number of unemployed", TRUE)
  )
  output$g3 <- renderBillboarder(
    draw_line("pce", "Personal consumption expenditures", FALSE)
  )
  output$g4 <- renderBillboarder(
    draw_line("pop", "Total population", FALSE)
  )
}

shinyApp(ui, server)