title: rxjs switchmap observable, save variables for final
body: <p>I need know a good practise for this problem.</p>
  
  <p>I am calling to three services concat with switchMaps, but I need a variable of first service for the last service. How was the best practice to do this?</p>
  
  <p>Example:</p>
  
  <pre><code>this.session.account.get()
  .switchMap(account =&gt; this.employerApi.get(account.accountId))
  .switchMap(employer =&gt; this.addressApi.get(employer.addressId))
  .filter(address =&gt; address.numer % 2)
  .subscribe(address =&gt; console.log(¿¿¿¿¿account.name?????, address.name));
  </code></pre>
  
  <p>Thanks for your help</p>