Show, hide, or toggle an offcanvas from the server

Control an offcanvas() panel from a Shiny server function. show_offcanvas() can either reveal a panel already in the UI by id, or take an offcanvas object (rendering it into the page if it isn't already there); hide_offcanvas() and toggle_offcanvas() act on a panel already in the UI, by id.

If a panel with the same id is already present in the page, show_offcanvas() simply reveals it; the object's content is not re-rendered or updated. To change the content of a persistent panel, update the inputs and outputs it contains rather than calling show_offcanvas() again.

Usage

show_offcanvas(offcanvas, ..., session = get_current_session())

hide_offcanvas(id, ..., session = get_current_session())

toggle_offcanvas(id, show = NULL, ..., session = get_current_session())

Arguments

offcanvas: One of: the id (a single string) of an offcanvas() panel already in the UI, which is revealed; list-like or tag content (e.g. htmltools::HTML() or a htmltools::tagList()), which is wrapped into a new anonymous offcanvas with default settings; or an offcanvas() object, which is rendered into the page (if needed) and shown. Note that a bare string used to be treated as body content for a new anonymous panel; it is now treated as an id lookup instead, and errors if it looks like body text (e.g. it contains whitespace or is empty).
...: Reserved for future extensions (currently ignored).
session: A Shiny session object (the default should almost always be used).
id: The id of an offcanvas in the UI. hide_offcanvas() also accepts an offcanvas() object whose id was set.
show: Whether to show (TRUE) or hide (FALSE) the offcanvas. The default (NULL) shows it if hidden and hides it if shown.

Value

Invisibly returns the offcanvas id (the generated id when show_offcanvas() is given an object without one).

Functions

show_offcanvas(): Render (if needed) and show an offcanvas.
hide_offcanvas(): Hide an offcanvas by id (or object).
toggle_offcanvas(): Toggle an offcanvas by id.

Module IDs

When controlling an offcanvas from a Shiny module, pass the module-local id to show_offcanvas() / hide_offcanvas() / toggle_offcanvas() — the same bare id you would use with input[[id]]. shiny::NS() / session$ns() is only applied when creating the panel's id in the UI. show_offcanvas() returns the local id, so it round-trips cleanly to hide_offcanvas() / toggle_offcanvas(). Do not pass a UI object whose id was already namespaced back to a server verb — it would double-namespace.

Examples

if (FALSE) { # rlang::is_interactive()
library(shiny)
library(bslib)

ui <- page_fluid(
  actionButton("show", "Show"),
  actionButton("hide", "Hide")
)
server <- function(input, output, session) {
  # Defined and revealed entirely from the server
  observeEvent(input$show, {
    show_offcanvas(
      offcanvas("Revealed from the server.", title = "Notice", id = "note")
    )
  })
  observeEvent(input$hide, hide_offcanvas("note"))
}
shinyApp(ui, server)

# Reveal an existing id'd panel already declared in the UI
ui <- page_fluid(
  actionButton("show", "Show"),
  offcanvas("Panel content", title = "Notice", id = "note")
)
server <- function(input, output, session) {
  observeEvent(input$show, show_offcanvas("note"))
}
shinyApp(ui, server)
}