title: Angular 6: Property 'of' does not exist on type 'typeof Observable'
body: <p>I am using <strong>Angular 6</strong> 
  using <strong>"rxjs": "^6.0.0",</strong></p>
  
  <p><strong>ERROR</strong> : Property 'of' does not exist on type 'typeof Observable'.</p>
  
  <pre><code>import { Injectable } from '@angular/core';
  import { TranslateLoader } from '@ngx-translate/core';
  import { Observable, Subject, pipe, of } from 'rxjs';
  
  
  @Injectable()
  export class MiTranslateLoaderService implements TranslateLoader {
  
    getTranslation(lang: string): Observable&lt;any&gt; {
      return Observable.of({
        lbl_select: 'Select',
      });
    }
  }
  </code></pre>