Enable live hot reloading for an RDesk application

rdesk_watch enables live monitoring of R source files and UI asset files (HTML, CSS, JS). When a UI file changes, the application automatically reloads the page. When an R script changes, the framework sources the modified module and automatically re-binds application event handlers.

Usage

rdesk_watch(app, enabled = TRUE)

Arguments

app

The RDesk App instance to monitor.

enabled

Logical. If TRUE (default), enables live monitoring. Set to FALSE to disable.

Value

The App instance (invisible), to allow method chaining.

Details

RDesk hot reload works by polling file modification times once per event loop iteration (roughly every 10 ms). When a change is detected:

R files

The modified file is source()d in the global environment. If a function named init_handlers exists in the global environment, it is called with the App instance so that message handlers are re-registered.

HTML/CSS/JS files

A __reload_ui__ message is sent to the frontend, triggering a full page reload in the WebView.

Hot reloading is designed for development only. It should not be enabled in bundled production builds.

See also

App

Examples

if (interactive()) {
  app <- App$new(title = "My App")
  rdesk_watch(app)  # or equivalently: app$watch(TRUE)
  app$run()
}