title: Only increment one item inside ngFor (Angular 2)
body: <p>I'm trying to create a little shopping cart with ionic 2 and angular 2. For now, here is my code : </p>
  
  <p>Front :</p>
  
  <pre><code> &lt;ion-card *ngFor="let person of people;let i = index" &gt;
  
          &lt;ion-card-header&gt;{{person.name.first}} {{person.name.last}} {{i}}&lt;/ion-card-header&gt;
  
          &lt;ion-item&gt;
          &lt;ion-icon name="add-circle" (click)="incrementQty(i)" item-right&gt;&lt;/ion-icon&gt;
          &lt;ion-input type="number" min="1" [value]="qty" [(ngModel)]="qty"&gt;&lt;/ion-input&gt;
          &lt;ion-icon name="remove-circle"(click)="decrementQty(i)" item-right&gt;&lt;/ion-icon&gt;
          &lt;/ion-item&gt;
  &lt;/ion-card&gt;
  </code></pre>
  
  <p>.ts file :</p>
  
  <pre><code>incrementQty(index:number){
    console.log(this.people[index]);
    this.qty += 1;
  }
  </code></pre>
  
  <p>My problem is that I only want to increment the clicked element, not all of them ! </p>
  
  <p>I'm new to angular 2 and don't know how to manage this problem, so thank you for your help ! </p>