chooser.R

## +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
## 'chooser.R' taken from the shiny-examples repository (https://github.com/rstudio/shiny-examples) under the MIT License
##+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
chooserInput <- function(inputId, leftLabel, rightLabel, leftChoices, rightChoices,
                         size = 5, multiple = FALSE) {

  leftChoices <- lapply(leftChoices, tags$option)
  rightChoices <- lapply(rightChoices, tags$option)

  if (multiple)
    multiple <- "multiple"
  else
    multiple <- NULL

  tagList(
    singleton(tags$head(
      tags$script(src = "chooser-binding.js"),
      tags$style(type = "text/css",
                 HTML(".chooser-container { display: inline-block; }")
      )
    )),
    div(id = inputId, class = "chooser",
        div(class = "chooser-container chooser-left-container",
            tags$select(class = "left", size = size, multiple = multiple, leftChoices)
        ),
        div(class = "chooser-container chooser-center-container",
            icon("fas fa-arrow-alt-circle-right", "right-arrow fa-3x"),
            tags$br(),
            icon("fas fa-arrow-alt-circle-left", "left-arrow fa-3x")
        ),
        div(class = "chooser-container chooser-right-container",
            tags$select(class = "right", size = size, multiple = multiple, rightChoices)
        )
    )
  )
}

registerInputHandler("shinyjsexamples.chooser", function(data, ...) {
  if (is.null(data))
    NULL
  else
    list(left = as.character(data$left), right = as.character(data$right))
}, force = TRUE)