title: How to iterate over firebase data object to list
body: <p><a href="https://i.stack.imgur.com/KzfDU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KzfDU.png" alt="firebase data"></a></p>
  
  <p><a href="https://i.stack.imgur.com/rWoH9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rWoH9.png" alt="logging data"></a></p>
  
  <pre><code> this.fb.getShoppingItems().then(result =&gt;{
     this.exercises=result;
     console.log("this exercise : ");
     console.log(this.exercises);
   })
  </code></pre>
  
  <p>I should list firebase data but getting error like below</p>
  
  <p>Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays.</p>
  
  <p>first pic is my firebase data structure and second one is console.log result.</p>
  
  <p>in html , I should iterate over exercises came from firebase data(interval_time, 
  name, rest_time, time)</p>
  
  <p>I think I should iterate over . for each date node like 20170710/20170711 ...
  How can I do that?</p>