insertUI {shiny}

Insert and remove UI objects

Description

These functions allow you to dynamically add and remove arbitrary UI into your app, whenever you want, as many times as you want. Unlike renderUI(), the UI generated with insertUI() is persistent: once it's created, it stays there until removed by removeUI(). Each new call to insertUI() creates more UI objects, in addition to the ones already there (all independent from one another). To update a part of the UI (ex: an input object), you must use the appropriate render function or a customized reactive function.

Usage

insertUI(
  selector,
  where = c("beforeBegin", "afterBegin", "beforeEnd", "afterEnd"),
  ui,
  multiple = FALSE,
  immediate = FALSE,
  session = getDefaultReactiveDomain()
)

removeUI(
  selector,
  multiple = FALSE,
  immediate = FALSE,
  session = getDefaultReactiveDomain()
)

Arguments

selector

A string that is accepted by jQuery's selector (i.e. the string s to be placed in a ⁠$(s)⁠ jQuery call).

For insertUI() this determines the element(s) relative to which you want to insert your UI object. For removeUI() this determine the element(s) to be removed. If you want to remove a Shiny input or output, note that many of these are wrapped in ⁠<div>⁠s, so you may need to use a somewhat complex selector — see the Examples below. (Alternatively, you could also wrap the inputs/outputs that you want to be able to remove easily in a ⁠<div>⁠ with an id.)

where

Where your UI object should go relative to the selector:

beforeBegin

Before the selector element itself

afterBegin

Just inside the selector element, before its first child

beforeEnd

Just inside the selector element, after its last child (default)

afterEnd

After the selector element itself

Adapted from https://developer.mozilla.org/en-US/docs/Web/API/Element/insertAdjacentHTML.

ui

The UI object you want to insert. This can be anything that you usually put inside your apps's ui function. If you're inserting multiple elements in one call, make sure to wrap them in either a tagList() or a tags$div() (the latter option has the advantage that you can give it an id to make it easier to reference or remove it later on). If you want to insert raw html, use ui = HTML().

multiple

In case your selector matches more than one element, multiple determines whether Shiny should insert the UI object relative to all matched elements or just relative to the first matched element (default).

immediate

Whether the UI object should be immediately inserted or removed, or whether Shiny should wait until all outputs have been updated and all observers have been run (default).

session

The shiny session. Advanced use only.

Details

It's particularly useful to pair removeUI with insertUI(), but there is no restriction on what you can use it on. Any element that can be selected through a jQuery selector can be removed through this function.

Examples

## Only run this example in interactive R sessions
if (interactive()) {
# Define UI
ui <- fluidPage(
  actionButton("add", "Add UI")
)

# Server logic
server <- function(input, output, session) {
  observeEvent(input$add, {
    insertUI(
      selector = "#add",
      where = "afterEnd",
      ui = textInput(paste0("txt", input$add),
                     "Insert some text")
    )
  })
}

# Complete app with UI and server components
shinyApp(ui, server)
}

if (interactive()) {
# Define UI
ui <- fluidPage(
  actionButton("rmv", "Remove UI"),
  textInput("txt", "This is no longer useful")
)

# Server logic
server <- function(input, output, session) {
  observeEvent(input$rmv, {
    removeUI(
      selector = "div:has(> #txt)"
    )
  })
}

# Complete app with UI and server components
shinyApp(ui, server)
}