Add callbacks for Shiny session eventsSource:
These functions are for registering callbacks on Shiny session events.
onFlush registers a function that will be called before Shiny flushes
the reactive system.
onFlushed registers a function that will be
called after Shiny flushes the reactive system.
registers a function to be called after the client has disconnected.
A callback function.
Should the function be run once, and then cleared, or should it re-run each time the event occurs. (Only for
A shiny session object.
These functions should be called within the application's server function.
All of these functions return a function which can be called with no arguments to cancel the registration.
onStop() for registering callbacks that will be
invoked when the application exits, or when a session ends.