title: Limitations on polymer conditional templates?
body: <p>I'm working on a set of conditional views based on the data available in a JSON object - effectively, show a media view if we have media to show, show a document view if we have merely text information to show, etc. The approach I've been using to date uses hasOwnProperty() to check the JSON object to determine the available data and work out the view template based on what's there. </p>
  
  <p>I've implemented something as a barebones version of this, but now I get nothing at all. The if seems to just kill the nested templates. Here's what I'm trying:</p>
  
  <pre><code>        &lt;template bind if="{{ posts[postid].hasOwnProperty('video') }}"&gt;
  
              &lt;div class="tileHeader"&gt;Posted by @{{ posts[postid].creator_id }} &lt;time-ago datetime="{{ posts[postid].creation_date }}"&gt;&lt;/time-ago&gt;&lt;/div&gt;
              &lt;div class="tile"&gt;
                  &lt;div class="heroTop" style="background-image: url({{ posts[postid].body }}) no-repeat"&gt;&lt;/div&gt;
                  &lt;div class="heroBottom"&gt;
                      &lt;div class="headline"&gt;{{ posts[postid].url_title }}&lt;/div&gt;
                      &lt;div class="postDesc"&gt;{{ posts[postid].url_description }}&lt;/div&gt;
                  &lt;/div&gt;
                  &lt;div class="attribution"&gt;
                      {{ posts[postid].url }}
                  &lt;/div&gt;
              &lt;/div&gt;
  
          &lt;/template&gt;
  
  
  
          &lt;template bind if="{{ posts[postid].hasOwnProperty('image') }}"&gt;
  
              &lt;div class="tileHeader"&gt;Posted by @{{ posts[postid].creator_id }} &lt;time-ago datetime="{{ posts[postid].creation_date }}"&gt;&lt;/time-ago&gt;&lt;/div&gt;
              &lt;div class="tile solo-view"&gt;
                  &lt;div class="heroSolo"&gt;
                      {{ posts[postid].body }}
                  &lt;/div&gt;
                  &lt;div class="attribution"&gt;
                      {{ posts[postid].url }}
                  &lt;/div&gt;
              &lt;/div&gt;
  
          &lt;/template&gt;
  </code></pre>
  
  <p>Two questions:
  1. Can this if statement work in this context, or does this need to be re-built as a filter?
  2. What happens in the case where both ifs are true for a given render?</p>