title: Check array length in angular 5 *ngIf displays nothing
body: <p>I am doing an *ngif to check if fitered results length is not 0 display items else display a template error.</p>
  
  <p>Unfortunately, the templateref works only when the filtered results has items.</p>
  
  <p>when it doesn't, the result.length displays nothing.</p>
  
  <pre><code>&lt;div *ngFor="let collection of collections | async | filterBy: ['title']: search as result"&gt;
         &lt;ng-container *ngIf='result?.length != 0; 
             then resultsIs else noresults'&gt;
         &lt;/ng-container&gt;
  
          &lt;ng-template #resultsIs&gt;
            &lt;a routerLink="/collections/c/{{collection.title | 
              slugify}}/{{collection.id}}" 
                 class="list-group-item list-group-item-action flex-column align-items-start"
            &gt;
          &lt;div class="d-flex w-100 justify-content-between"&gt;
            &lt;h5 class="mb-1 text-primary"&gt;&lt;u&gt;{{collection.title}}&lt;/u&gt;&lt;/h5&gt;
             &lt;small&gt;{{collection.updatedAt}}&lt;/small&gt;
             &lt;/div&gt;
             &lt;p class="text-muted" &gt;{{collection.description}}&lt;/p&gt;
             &lt;small&gt;{{collection.username}}&lt;/small&gt;
        &lt;/a&gt;
      &lt;/ng-template&gt;
  
      &lt;ng-template #noresults&gt;
       &lt;div class="alert alert-info"&gt;
      &lt;strong&gt;No Match Found!&lt;/strong&gt;
       Widen your search.&lt;/div&gt;
         &lt;/ng-template&gt;
       &lt;/div&gt;
  </code></pre>
  
  <p>How can I check correctly if this object array length is less than zero so I can display this part of template </p>
  
  <pre><code> &lt;ng-template #noresults&gt;
          &lt;div class="alert alert-info"&gt;&lt;strong&gt;
            No Match Found!&lt;/strong&gt; Widen your search.
           &lt;/div&gt;
  &lt;/ng-template&gt;
  </code></pre>