title: toggle css class on clicked element only
body: <p>Two div elements have values 1 and 2. Every time when each element is clicked I want to toggle css class.
  This provided solution always toggle css class for both (all) elements.</p>
  
  <pre><code>&lt;div (click)="toggleClass()" [class.active]="isActive"&gt;1&lt;/div&gt;
  &lt;div (click)="toggleClass()" [class.active]="isActive"&gt;2&lt;/div&gt;
  
  export class MyComponent{
    isActive = false;  
    constructor(){}  
    toggleClass() {
       this.isActive = !this.isActive;
    }
  }
  </code></pre>