title: What the difference between setting value of variables within the constructor or outside it
body: <p>What's the difference between this:</p>
  
  <pre><code>export class List {
    categories: any[];
    constructor() {
      this.categories = ['First Class', 'Second Class', 'Economy'];
    }
  }
  </code></pre>
  
  <p>And this:</p>
  
  <pre><code>export class List {
    categories: any[] = ['First Class', 'Second Class', 'Economy'];
    constructor() {
    }
  }
  </code></pre>
  
  <p>Both compile to the same Javascript code. Considering, in this particular example, the class is never going to be instantiated with passed in values, am I OK sticking with the second option of setting the values outside the constructor function?</p>
  
  <p>This is in the context of Angular2 class components using typescript.</p>