title: Typescript - type 'false' is not assignable to type 'true'
body: <p>I am learning angular 2, and in this example where I set the variable for isLoading to true, and then change it to false, once I fetch the data I need, I get the error:</p>
  
  <blockquote>
    <p>Typescript - type 'false' is not assignable to type 'true'</p>
  </blockquote>
  
  <p>This is the code:</p>
  
  <pre><code>export class AppComponent implements OnInit {
      isLoading: true;
  
      constructor(private _articleService: ArticleService, private _postService: PostService){}
  
      ngOnInit(){
        this.articles = this._articleService.getArticles();
        this._postService.getPosts()
          .subscribe(posts =&gt; {
            this.isLoading = false;
            console.log(posts[0].title);
          });
      }
  </code></pre>