title: make shiny app UI dependent on URL parameter
body: <p>I would like to create alternative UIs for my app depending on URL parameter. Specifically, I'd like to use the drop-down pickerInput from shinyWidgets instead of checkboxGroupInput, but only if parameter mini=TRUE is passed via the URL</p>
  
  <pre><code>library(shinyWidgets)
  
  nazwy=c('Warszawa', 'Krakow', 'Gdansk')
  
  ui&lt;-fluidPage(
   if (mini) {
      pickerInput(inputId = "miasto", choices = nazwy,multiple = TRUE)
   } else {
    checkboxGroupInput('miasto', nazwy)
   })
  </code></pre>
  
  <p>Can I somehow do it using the conditionalPanel, or is renderUI my only option?</p>
  
  <p>Alternatively, can I make the pickerInput or the checkboxGroupInput appear depending on the window width?</p>
  
  <p>UPDATE</p>
  
  <p>Option 1 given below is a working answer to my initial question, making UI dependent on URL. Option 2 is a better solution for this particular case - adapting UI to window size. HOWEVER, for option 2 to work properly, one needs another variable to store selections, so that the select/pickerInput doesn't go back to default selection every time window is resized. I edited the code accordingly.</p>