title: Ngx-charts can't load bar charts directly with async pipe in angular
body: <p>My problem is similar to this <a href="https://stackoverflow.com/q/46629702/1712016">stackoverflow post</a></p>
  
  <p>When I use async pipe to observe data from firebase and show it in chart, I can see the chart but prompt null error in console. Without async pipe, all errors are gone but I can't fetch data (duh it's async data). Help me please.</p>
  
  <p><a href="https://i.stack.imgur.com/keaOZ.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/keaOZ.jpg" alt="Barchart"></a></p>
  
  <p><a href="https://i.stack.imgur.com/LORVJ.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LORVJ.jpg" alt="Barchart code"></a></p>
  
  <p><a href="https://i.stack.imgur.com/XuepZ.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/XuepZ.jpg" alt="Error"></a></p>
  
  <p><a href="https://i.stack.imgur.com/20VzX.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/20VzX.jpg" alt="Empty chart"></a></p>