title: Best way to read and update a value of a BehaviorSubject
body: <p>since it's well known that use getValue() method on a BehaviorSubject should be avoided <a href="https://stackoverflow.com/questions/37089977/how-to-get-current-value-of-rxjs-subject-or-observable/45227115">link</a>
  I'm wondering what's the best way to read and updated a BehaviorSubject.</p>
  
  <p>In my case I've a BehaviorSubject storing an array of objects and when I click on a button I should push another object to the array and emit the new value to all the subscribers.</p>
  
  <p>Right now I'm doing:</p>
  
  <pre><code>this.myBehaviorSubject.next([
      ...this.myBehaviorSubject.value,
      { new object }
  ])
  </code></pre>
  
  <p>Is there a better approach?</p>
  
  <p>Thanks!!</p>