title: Angular Typescript changing Object property in array not updating view
body: <p>I'm working on learning Typescript and Angular and I have question as to why my view isn't updating when updating an array value that is set to a object i have defined. I suspect it's something to do with me losing the context to this? Do I need to run ngZone somehow? (I've tried with no success). I suspect this it's something easy or a concept I'm overlooking.</p>
  
  <pre><code>cardItems = {
    addUser: true,
    inventory: false
  }
  cardCollapseItems = [
  {
    label: "addUser",
    item: this.cardItems.addUser
  },
  {
    label: "inventory",
    item: this.cardItems.inventory
  },
  
  collapseCard(value){
   let index = this.cardCollapseItems.findIndex(item =&gt; item.label === value)
   let cardItem = this.cardCollapseItems[index]
   cardItem.item ? cardItem.item = false : cardItem.item = true;
  }
  
   &lt;ion-card-header (click)="collapseCard('addUser')"&gt;
   &lt;ion-card-content [hidden]="cardItems.addUser" &gt;
  </code></pre>