title: How to access global variable in Angular 2 Component
body: <p>I want to access google api library from angular 2 module in typescript.
  How to do that.
  When i try to access (gapi) i get the undefined. is there any NPM module that work as typescript library in angular 2 to which i can use or i have to use the js file.</p>
  
  <p>Following is the module code and library reference:</p>
  
  <pre><code> &lt;script src="https://apis.google.com/js/client.js?onload=handleClientLoad"&gt;&lt;/script&gt;
  </code></pre>
  
  <p>.</p>
  
  <pre><code>    @Component({
  
      selector: "main-app",
      template: "{{title}}",
      providers: [HTTP_PROVIDERS, AuthService]
  
  })
  export class AppComponent implements OnInit {
      public title: string = '';
      constructor(private _authService: AuthService) {
          var gapi: any;
          console.log(gapi); // undefined
      }
      ngOnInit() {
  
          this._authService.getAuthSettings().subscribe((set: AppSetting) =&gt; {
              this.title = set.Scopes;
          });
      }
  
  };
  </code></pre>