R shiny select part of HTML file by id - html

Question

I have an application that displays data on indicators. Each indicator (30+) has a definition. We have this definition of all indicators in a single html file (easier to maintain than 30 different ones).
In my ShinyApp, I want to show only the section relevant to the indicator selected, not the full document.
I was wondering how this could be done....
Here is an example that is only showing the full 'document' instead of the part which is selected in the sidebar:
documentation <- structure("<div> <div id=\"part1\"> <h1>Part 1</h1> <p>This is part 1 out of 2</p> <p> </p> </div> <div id=\"part2\"> <p> </p> <h1>Part 2</h1> <p>This is part 2 out of 2.</p> </div> </div>", html = TRUE, class = c("html", "character"))
documentation
library(shiny)
library(shinydashboard)
ui <- dashboardPage(
dashboardHeader(),
dashboardSidebar(
selectInput(inputId = "part",label = "Select the part you want to see", choices = c("part1", "part2"))
),
dashboardBody(
uiOutput("section")
)
)
server <- function(input, output) {
output$section <- renderUI({
HTML(documentation) # This needs subsetting based on input$part
})
}
shinyApp(ui, server)

Answer 1

I came up with a quick and dirty solution, by manipulating the HTML as a string.
I wonder if there are more elegant methods though...
library(shiny)
library(shinydashboard)
ui <- dashboardPage(
dashboardHeader(),
dashboardSidebar(
selectInput(inputId = "part",label = "Select the part you want to see", choices = c("part1", "part2"))
),
dashboardBody(
uiOutput("section")
)
)
server <- function(input, output) {
output$section <- renderUI({
# HTML(documentation)
t1 <- strsplit(documentation, "<div")[[1]][grepl(input$part, strsplit(documentation, "<div")[[1]])]
t2 <- paste0("<div", t1)
t2 <- gsub("</div> </div>", "</div>", t2)
HTML(t2)
})
}
shinyApp(ui, server)