Call one browser-side method on a target element — wa_call

Sends a one-way command from the Shiny server that invokes a browser-side method on the element identified by DOM id.

Usage

wa_call_method(
  id,
  method,
  args = list(),
  session = shiny::getDefaultReactiveDomain()
)

Arguments

id: DOM id of the target browser element.
method: Scalar method name to invoke on the target element.
args: Optional list of positional arguments to pass to the method. These should be serializable through Shiny's custom-message transport. In practice, prefer JSON-like scalar values or nested lists that map cleanly to browser values. Do not expect R functions, language objects, or HTML tags to serialize into useful method arguments.
session: Shiny session object. Defaults to the current reactive domain.

Value

Invisibly returns NULL.

Details

wa_call_method() is a narrow package-level escape hatch for advanced cases where a Web Awesome component method needs to be triggered from server logic but is not covered by a generated helper. It does not validate whether the requested method exists for the targeted component.

This helper is complementary to generated component bindings and update helpers. It is not part of upstream component coverage and does not expand the generated per-component API surface.

On the server side, wa_call_method() validates only its R helper inputs, such as the target id, method name, argument list, and session. It does not validate whether the requested method exists on the browser-side element.

In the browser runtime, the command layer validates that the target DOM id resolves to an element, that a method name was supplied, and that the named member is callable on the target element before invoking it. Command-layer warnings are controlled by the package warning registry, especially the command_layer key. For option details, see the Package Options article.

Examples

# \donttest{
library(shiny)
library(shiny.webawesome)

ui <- webawesomePage(
  wa_button("Show dialog", id = "show_dialog"),
  wa_dialog("Dialog body", id = "dialog")
)

server <- function(input, output, session) {
  observeEvent(input$show_dialog, {
    wa_call_method("dialog", "show", session = session)
  })
}

app <- shinyApp(ui, server)
stopifnot(inherits(app, "shiny.appobj"))

# Run `app` interactively to launch this example application.
# }