create dynamically an accordion with lapply in bs4Dash

Question

I try to dynamically create an accordion bast on a dataframe. Despite many try-outs I did not manage to get it working. Below the code of an example dashboard with two examples:

1. lappy: not working (lijst1)
2. program each item: working (lijst2)

see example below.

Hopefully someone can help?

library(bs4Dash)
library(shiny)

dataset <- data.frame(
  title = c("title 1", "title 2")
  , tekst = c("text 1", "text 2")
)

# create using lapply (flexible)
lijst1 <- accordion(
  id = "test1"
  , lapply(seq_along(dataset$title), function(i){
    accordionItem(title = dataset$title[i], dataset$tekst[i])
  })
)

# create by specify each item
lijst2 <- accordion(
  id = "test2"
  , accordionItem(title = "title 1 simple", "text 1 simple")
  , accordionItem(title = "title 1 simple", "text 2 simple")
)


ui <- dashboardPage(
  dashboardHeader()
  , dashboardSidebar()
  , dashboardBody(
    h2("Doesn't work")
    , lijst1
    , h2("Works")
    , lijst2
  )
)

server = function(input, output) {}

shinyApp(ui = ui, server = server)

Answer 1

One option to achieve your desired result would be to make use of do.call which works quite well with lapply as it allows you to pass function arguments as a list:

library(bs4Dash)
library(shiny)

dataset <- data.frame(
  title = c("title 1", "title 2"),
  tekst = c("text 1", "text 2")
)

# create using lapply (flexible)
lijst1 <- do.call("accordion", c(
  list(id = "test1"),
  lapply(seq_along(dataset$title), function(i) accordionItem(title = dataset$title[i], dataset$tekst[i]))
))

# create by specify each item
lijst2 <- accordion(
  id = "test2",
  accordionItem(title = "title 1 simple", "text 1 simple"),
  accordionItem(title = "title 1 simple", "text 2 simple")
)


ui <- dashboardPage(
  dashboardHeader(),
  dashboardSidebar(),
  dashboardBody(
    h2("Doesn't work"),
    lijst1,
    h2("Works"),
    lijst2
  )
)

server <- function(input, output, session) {

}

shinyApp(ui, server)