title: Calling a typescript function named in a variable
body: <p>I am working on Ionic2 app. I am calling a function from a a Page. Is it possible that I use a variable name in function call. e.g.</p>
  
  <p>original code: <code>this._userDataService.getGrandQuestionsFromServer(this.passedId, newLevel)</code></p>
  
  <p>expected code::</p>
  
  <pre><code>this._userDataService.get`${this.questionModuleName}`QuestionsFromServer(this.passedId, newLevel) 
  </code></pre>