title: What should go inside the brackets of the "constructor" function in ionic?
body: <p>I know that in the <code>constructor</code> I load some dependencies as plugins or load providers that I will use in the class. but I do not know what should go inside the brackets? in some cases it is empty, but in others, variables are defined. What is the best practice and when it is agreed within these brackets, what should be included?</p>
  
  <pre><code>constructor(
   public navCtrl: NavController // for example
  ){
   ????
  }
  </code></pre>