title: what is the best practice to call a function in html using angular2?
body: <p>i am calling a function using html binding expression(template interpolation) in angular2 while doing this the console statements are printing continuously. 
  Is this is the only way to do or any different ways to call a function in html. i have use the similar syntax in angularjs-v1 have no issues! any suggestions will be appreciated. Thanks!  </p>
  
  <h2>html</h2>
  
  <pre><code> &lt;button ion-button (click)="addProduct(totalSingleItem,getTotalItemPrice(totalSingleItem))" &gt;addProduct
            &lt;span&gt;: {{getTotalItemPrice(singleItem) * singleItem.quantity}}&lt;/span&gt;
        &lt;/button&gt;
  </code></pre>
  
  <h2>ts</h2>
  
  <pre><code>private getTotalItemPrice(ITEM) {
  return totalPrice; //(eg: 75$)
  
  }
  </code></pre>