title: What is the purpose of SwUpdate.activateUpdate() in Angular?
body: <p><a href="https://angular.io/guide/service-worker-communications#forcing-update-activation" rel="noreferrer">Angular documentation</a> provides following example to activate an SW update:</p>
  
  <pre><code>constructor(updates: SwUpdate) {
    updates.available.subscribe(event =&gt; {
      if (promptUser(event)) {
          updates.activateUpdate().then(() =&gt; document.location.reload());
      }
    });
  }
  </code></pre>
  
  <p>From what I observe, the call itself is not sufficient to activate new version, reload is necessary. However <code>document.location.reload()</code> is sufficient even without <code>activateUpdate()</code> call.</p>
  
  <p>What is the purpose of <code>activateUpdate()</code> call? Why call it at all when reload suffice?</p>