title: Module '/node_modules/rxjs/observable/TimerObservable' has no exported member 'TimerObservable' in Angular 6
body: <p>While migrating application from Angular 5 to Angular 6 getting below error,</p>
  
  <pre><code>Module '/node_modules/rxjs/observable/TimerObservable' has no exported member 'TimerObservable'.
  </code></pre>
  
  <p>Code:</p>
  
  <pre><code>import { Injectable } from '@angular/core';
  import { TimerObservable } from 'rxjs/observable/TimerObservable';
  import { Observable } from 'rxjs';
  
  @Injectable()
  export class TimerTestScv {
  
      static fetchTimer(interval: number, initialDelay: number): Observable&lt;number&gt;         
      {
         return TimerObservable.create(initialDelay, interval);
      }
  }
  </code></pre>
  
  <p>rxjs package used:</p>
  
  <pre><code>"rxjs": "^6.2.2",
  </code></pre>