title: bootstrap class.active not working in Angular 8
body: <p>[class.active] is not working in my code some time before it is working that time i was using angular and old version Bootstrap but now upgrade on angular 8 and bootstrap 4.2.1 it is not working code is here</p>
  
  <pre><code>&lt;a *ngFor="let cat of categoryArray;let i=index;"
                  routerLink="/" 
                  [queryParams]="{category: cat.CategoryId}"
                  class="list-group-item list-group-item-action" 
                  [class.active]= "category === cat.CategoryId"   
                  (click)="fileUploadComponent.Save()"
                  &gt;               
                    {{cat.Name}}
                &lt;/a&gt;
  </code></pre>
  
  <p>problem is, condition of following line always false but in fact it should not.</p>
  
  <pre><code>[class.active]= "category === cat.CategoryId"
  </code></pre>
  
  <p>What is the problem?</p>