Cloning and removing elements

Introduction

Sometimes you want the ability to drag an item multiple times from a list, in other words the ability to “clone” the items of the original list.

And you may also then want the ability to remove cloned items, possibly by dragging to a “bin” or “remove item” list.

Cloning an element

To clone an element from a list, you must add the pull = "clone" option to the sortable_options argument::

library(sortable)
sortable_js(
  "sort1",
  options = sortable_options(
    group = list(
      pull = "clone",
      name = "sortGroup1",
      put = FALSE
    ),
    onSort = sortable_js_capture_input("sort_vars")
  )
)

Removing an element

To remove an element from the dropped list, one option is to create a “bin” area by using the JavaScript code:

this.el.removeChild(evt.item);

Then add to this JavaScript to the onAdd element of sortable_options(). To pass your JavaScript code to R, use the htmlwidgets::JS() function:

sortable_js(
  "sortable_bin",
  options = sortable_options(
    group = list(
      group = "sortGroup1",
      put = TRUE,
      pull = TRUE
    ),
    onAdd = htmlwidgets::JS("function (evt) { this.el.removeChild(evt.item); }")
  )
)

Full example

And the full code:

## Example shiny app to demonstrate cloning and other sortable_options

library(shiny)
library(htmlwidgets)
library(sortable)
library(magrittr)

icon_list <- function(x){
  lapply(
    x,
    function(x) {
      tags$div(
        icon("arrows-alt-h"),
        tags$strong(x)
      )
    }
  )
}


ui <- fluidPage(
  fluidRow(
    class = "panel panel-heading",
    div(
      class = "panel-heading",
      h3("Illustration of sortable_options()")
    ),
    fluidRow(
      class = "panel-body",
      column(
        width = 4,
        tags$div(
          class = "panel panel-default",
          tags$div(
            class = "panel-heading",
            icon("arrow-right"),
            "Drag from here (items will clone)"
          ),
          tags$div(
            class = "panel-body",
            id = "sort1",
            icon_list(c(
              "A",
              "B",
              "C",
              "D",
              "E"
            ))
          )
        )
      ),
      column(
        width = 4,
        # analyse as x
        tags$div(
          class = "panel panel-default",
          tags$div(
            class = "panel-heading",
            icon("exchange"),
            "To here(max 3 items)"
          ),
          tags$div(
            class = "panel-body",
            id = "sort2"
          )
        ),
        # analyse as y
        tags$div(
          class = "panel panel-default",
          tags$div(
            class = "panel-heading",
            icon("exchange"),
            "Or here"
          ),
          tags$div(
            class = "panel-body",
            id = "sort3"
          )
        )

      ),
      column(
        width = 4,
        # bin
        tags$div(
          class = "panel panel-default",
          tags$div(
            class = "panel-heading",
            icon("trash"),
            "Remove item"
          ),
          tags$div(
            class = "panel-body",
            id = "sortable_bin"
          )
        )

      )
    )
  ),
  sortable_js(
    "sort1",
    options = sortable_options(
      group = list(
      pull = "clone",
        name = "sortGroup1",
        put = FALSE
      ),
      # swapClass = "sortable-swap-highlight",
      onSort = sortable_js_capture_input("sort_vars")
    )
  ),
  sortable_js(
    "sort2",
    options = sortable_options(
      group = list(
        group = "sortGroup1",
        put = htmlwidgets::JS("function (to) { return to.el.children.length < 3; }"),
        pull = TRUE
      ),
      swapClass = "sortable-swap-highlight",
      onSort = sortable_js_capture_input("sort_x")
    )
  ),
  sortable_js(
    "sort3",
    options = sortable_options(
      group = list(
        group = "sortGroup1",
        put = TRUE,
        pull = TRUE
      ),
      swapClass = "sortable-swap-highlight",
      onSort = sortable_js_capture_input("sort_y")
    )
  ),
  sortable_js(
    "sortable_bin",
    options = sortable_options(
      group = list(
        group = "sortGroup1",
        put = TRUE,
        pull = TRUE
      ),
      onAdd = htmlwidgets::JS("function (evt) { this.el.removeChild(evt.item); }")
    )
  )

)

server <- function(input, output) {
  output$variables <- renderPrint(input[["sort_vars"]])
  output$analyse_x <- renderPrint(input[["sort_x"]])
  output$analyse_y <- renderPrint(input[["sort_y"]])


  x <- reactive({
    x <- input$sort_x
    if (is.character(x)) x %>% trimws()
  })

  y <- reactive({
    input$sort_y %>% trimws()
  })

}
shinyApp(ui, server)