Historically this function was used in ui.R files to register a user interface with Shiny. It is no longer required as of Shiny 0.10; simply ensure that the last expression to be returned from ui.R is a user interface. This function is kept for backwards compatibility with older applications. It returns the value that is passed to it.
shinyUI(ui)A user interace definition
The user interface definition, without modifications or side effects.