title: Angular 2: what differences between comparison operators == and === in ngIf directive
body: <p>I don't understand why these two operators exist. In case of boolean comparison both == and === seem to work, but in case of enum comparison only '==' works:</p>
  
  <pre><code>&lt;div class="interventionGroup"&gt;
  
      &lt;div class="interventionGroupHeader transition_1s" (click)="onClickHeader()"&gt;
          {{GroupName}}
          &lt;div *ngIf="expanded == true" class="expand-icon"&gt;&lt;i class="material-icons"&gt;expand_less&lt;/i&gt;&lt;/div&gt;  &lt;!-- WORKS --&gt;
          &lt;div *ngIf="expanded === false" class="expand-icon"&gt;&lt;i class="material-icons expand-icon"&gt;expand_more&lt;/i&gt;&lt;/div&gt; &lt;!-- WORKS --&gt;
      &lt;/div&gt;
  
      &lt;button *ngIf="GroupType == GroupTypeEnum.mesInterventions"&gt;dfdsfsd&lt;/button&gt; &lt;!-- WORKS --&gt;
  
      &lt;div style="list-style-type:none" *ngIf="expanded === true"&gt;
          &lt;div *ngFor="let intervention of interventions"
              (click)="onClick(intervention)"&gt; 
              &lt;intervention-button [intervention]="intervention"&gt;&lt;/intervention-button&gt;
          &lt;/div&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>