title: Get the resulting URL from a Leaflet map in R
body: <p>I'm wondering if it's possible to get the final URL of a <code>leaflet</code> map in R. I've attempted to get at it with the following, but the URL has placeholders that are filled in, and I'm hoping to get the final URL.</p>
  
  <pre><code>library(leaflet)
  m = leaflet() %&gt;%
    addTiles() %&gt;%
    addMarkers(lng=-73.9851, lat=40.7589)
  
  m$x$calls[[1]]$args[[1]][1]
  [1] "http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
  </code></pre>
  
  <p>Any insight would be appreciated.</p>