title: Angular ngbTypeahead doesn't reset value of input on blur
body: <p>I'm using the bootstrap <a href="https://ng-bootstrap.github.io/#/components/typeahead/examples" rel="nofollow noreferrer">ngbTypeahead</a> of Angular2+ and I want to clean the input when lose focus and no item ware selected. </p>
  
  <p>But the value doesn't clean when the typeahead shows options to select, even if I lose the input focus and dont select any item.</p>
  
  <p><strong>Like This:</strong></p>
  
  <p><a href="https://i.stack.imgur.com/lP4PJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/lP4PJ.png" alt="enter image description here"></a></p>
  
  <p><strong>HTML:</strong></p>
  
  <pre><code>&lt;input type="text"
          id="obj"
          formControlName="obj"
          class="form-control"
          [class.is-invalid]="searchFailed"
          [ngbTypeahead]="filter"
          (selectItem)="selectObj($event.item)"
          (blur)="blurObj()" /&gt;
  </code></pre>
  
  <p><strong>Typescript:</strong></p>
  
  <pre><code>filter = (text$: Observable&lt;string&gt;) =&gt; {
      return text$.pipe(
          debounceTime(200),
          distinctUntilChanged(),
          tap(() =&gt; this.objSelected = null),
          switchMap( (term: string) =&gt; {
            if(term.length &lt; 3) {            
              return [];
            } else {
              this.searching = true;
              return this.service.filter(term as string)
                .pipe(
                  tap(() =&gt; this.searchFailed = false),
                  catchError(() =&gt; {
                      this.searchFailed = true;
                      this.searching = false;
                      return [];
                  })
                );
            }
          }),
          tap(() =&gt; this.searching = false)
      );
  }
  
  selectObj(obj: any) {
      this.objSelected = obj;
  }
  
  blurObj() {
      if(!this.objSelected) {
        this.form.get('obj').setValue('');
      }
  }
  </code></pre>
  
  <p><strong>This strange thing happens too:</strong></p>
  
  <p><a href="https://i.stack.imgur.com/UOG0j.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UOG0j.png" alt="enter image description here"></a></p>
  
  <p><strong>Running Sample:</strong>
  <a href="https://stackblitz.com/edit/angular-ivy-spzwkm" rel="nofollow noreferrer">https://stackblitz.com/edit/angular-ivy-spzwkm</a></p>
  
  <p><strong>PS:</strong> Type 3 or more characteres to test.</p>