title: Angular subscribe method is calling multiple time
body: <p>On Angular 6 I have created one service</p>
  <pre><code>@Injectable({ providedIn: 'root' })
  export class CrossEventService {
    public refresh$: EventEmitter&lt;string&gt; = new EventEmitter&lt;string&gt;();
    public refreshSections(event: any) {
      this.refresh$.emit(event)
    }
  }
  </code></pre>
  <p>now from the Other component ngOnint method if that particular method is invoked</p>
  <p>invoking method like</p>
  <pre><code>this.CrossEventService.refreshSections(&quot;&quot;); 
  </code></pre>
  <p>and now I am checking on the other component ngOnInit method</p>
  <pre><code> ngOnInit() {
      this.CrossEventService.refresh$.subscribe(data =&gt; {
        if (data) {
          // call whatever method i need to call from my current component
        }
      });
  </code></pre>
  <p>but in some place the above subscribe method is calling multiple times?</p>