Register Reactives for Reproduction

Record reactives against the current Shiny session, so that reprex_packages() and reprex_lockfile() can be called with no arguments and still cover the whole application.

This avoids having to return reactives out of every module purely so a single top-level call can see them. Each module registers what it owns, and the session holds the collection.

Namespacing

Registrations are namespaced by the calling module, so two modules may register reactives of the same name without collision, and re-registering the same name in the same module replaces the previous entry rather than adding a duplicate.

When to Register

Registering does not evaluate the reactive. Packages are resolved by reading the expression held in the reactive, so it may be registered while still gated behind shiny::req() or inputs that have yet to be set. Registering at module setup is therefore both safe and preferred, as it does not depend on the user having visited the output first.

Session Scope

The collection lives on the session, so it is discarded when the session ends and is never shared between concurrent users of the same application.

Usage

register_reactives(..., session = shiny::getDefaultReactiveDomain())

Arguments

...: One or more shiny::reactive objects to register. Names are taken from the arguments, so register_reactives(summary_tbl) registers under "summary_tbl". Supply names explicitly to override.
session: The Shiny session to register against. Defaults to the current reactive domain, which inside a module is that module's session.

Value

The registered reactives, invisibly, as a named list.

Examples

if (FALSE) { # interactive()
library(shiny)

summaryServer <- function(id) {
  moduleServer(id, function(input, output, session) {
    summary_tbl <- reactive(purrr::keep(iris, is.numeric))

    register_reactives(summary_tbl)

    summary_tbl
  })
}

# Elsewhere in the application, with no reactives threaded through:
# reprex_lockfile()
}