title: remove multiple elements from an observable array in angular
body: <hr>
  
  <p>Hi All,</p>
  
  <p>I'm pretty new to angular and rxjs. I have two beservable arrays which one of them 'A' has only subset of the other observable array 'B'. I need to remove elements from 'A' from 'B'. How do I achieve that?  </p>