title: How to call a function from global API in Angular expressions?
body: <p>Angular.js provides a banch of global functions like angular.lowercase, angular.isArray etc. </p>
  
  <p>Suppose I have a string in my scope:</p>
  
  <pre><code>function MyController($scope) {
     $scope.myString = "TEST"
  }
  </code></pre>
  
  <p>Calling angular.lowercase has no effect:</p>
  
  <pre><code>{{lowercase(myString)}}
  {{angular.lowercase(myString)}}
  </code></pre>
  
  <p>How can I call such function in my template?</p>
  
  <p><strong>UPDATE</strong></p>
  
  <p>Example with angular.isArray</p>
  
  <pre><code>&lt;div ng-show="isArray(myVar)"&gt;...&lt;/div&gt;
  </code></pre>