title: Angular - How to call make an HTTP Call that has multiple subscribers / subjects
body: <p>Sorry for the confusing title, it was hard wording it.</p>
  
  <p>I have an angular service that calls an API and gets a list of pages.  These pages are subscribed to from multiple components.  With this in mind i use BehaviorSubjects to make sure each subscriber gets the updates. </p>
  
  <p>When I want to add a new page, i need to submit a HTTP POST request to the server, and then handle the response. In handling it, i need to update the array and then call next() to send the updates around to the subscribers.  This requires me to have a subscriber on the HTTP call (at least i think it does) so that i can call next().  However, at the same time as calling next, i also want the component to update and let the user know its been completed.</p>
  
  <p>Here is a stackblitz example.  app.component.ts line 38 has a call to the service to create a page. Commented out below, is a section of code that would subscribe and set the isSaving variable to false.  however, i cannot subscribe to the method as it already has a subscription inside the pages.service.ts file.</p>
  
  <p><a href="https://stackblitz.com/edit/angular-abi4mn" rel="nofollow noreferrer">https://stackblitz.com/edit/angular-abi4mn</a></p>
  
  <p>I'm hoping the example makes more sense than my ramblings, apologies if the explanation is poor. </p>