title: Knockout observableArray in TypeScript
body: <p>What is the proper way to initialize a Knockout observableArray in a TypeScript class?</p>
  
  <p>I am doing something like this:</p>
  
  <pre><code>   module ViewModel { 
  
          declare var ko;
  
          export class IndexPageViewModel {       
  
                  agencies: any;                   
  
                  constructor () {               
                      this.agencies = ko.observableArray([]);              
                  }                                                                                                   
          }
      }
  
  
  var ivm = new ViewModel.IndexPageViewModel();
  ivm.agencies.push({name: "name", alias : "alias"});
  for (var i = 0; i &lt; ivm.agencies.length; i++){
      alert(ivm.agencies[i].name);
   }
  </code></pre>
  
  <p>Looks simple enough, but when I attempt to access the agencies property as indicated,  execution hangs.  Did I miss something?</p>