add CSS class to shiny textOutput

Question

I need to add a CSS class to a series of textOutput in a shiny app.

When I try, e.g.:

textOutput('text', class = 'error')

I get:

Warning: Error in textOutput: unused argument (class = "error")

It is possible to alter the CSS of the id of that textOutput. However, my ids are generated dynamically, so that is not a good solution. A possible alternative would be to 'grab' all ids that begin with/contain "error" (e.g. "error1", "error2"), but I am not sure if this is possible within my CSS style sheet.

Answer 1

A simple was to do this is using the shiny tagAppendAttributes function. I normally find it easier to pipe the HTML output of shiny output objects into it like so:

library(shiny)
library(magrittr)

textOutput("foo") %>% 
  tagAppendAttributes(class = 'error')

Which produces the following output, which contains the error class.

<div class="shiny-text-output error" id="foo"></div>

---

You can also do the same thing with styles

textOutput("foo") %>% 
  tagAppendAttributes(style= 'color:green;')

<div id="foo" class="shiny-text-output" style="color:green;"></div>