How to use ng-show with ng-repeat filtered?

Question

Here is my json (each object can be assigned to more than one category):

[
 { "title" : "titel1",
   "description" : "description1",
   "data": {
             "categoryList" : [
                                { "categoryName" : "category1" }
                               ]
            }
 },
 { "title" : "titel2",
   "description" : "description2",
   "data": {
             "categoryList" : [
                                { "categoryName" : "category1" }
                               ]
            }
 },
 { "title" : "titel3",
   "description" : "description3",
   "data": {
             "categoryList" : [
                                { "categoryName" : "category2" }
                               ]
            }
 },
 ... and so on
]

The div tags display the content for each category. I'd like to show the message "No content available", when no content is assigned to a category. No sure if something like ng-show="!content. "this category" .length" would work.

<!-- category 1 -->
<div>
  <ul>
    <li ng-repeat="item in content | filter:{'data':'category1'}">
    {{item.title}} - {{item.description}}
    </li>
    <li ng-show="?????">No content available</li> 
  </ul>
</div>

<!-- category 2 -->
<div>
  <ul>
    <li ng-repeat="item in content | filter:{'data':'category2'}">
    {{item.title}} - {{item.description}}
    </li>
    <li ng-show="?????">No content available</li>  
  </ul>
</div>

...

Answer 1

You can save the array returned by the filter, and use its length to toggle ng-show:

<li ng-repeat="item in (filteredContent = (content | filter:{'data':'category1'}))">
...
<li ng-show="filteredContent.length == 0">No content available</li>

In this demo http://plnkr.co/7kMjojVAkCkTR8XQlunB, try changing the filter so that nothing is matched.