title: Angular4 - do I need to unsubscribe from setTimeout calls?
body: <p>In a few places I have needed to call setTimeout, eg:</p>
  
  <pre><code>setTimeout(() =&gt; this.isSaving[index] = false, 500);
  </code></pre>
  
  <p>When my component is destroyed, will that timeout continue to emit? In other words do I need to capture the returned observable, like this:</p>
  
  <pre><code>this.subTimeout = setTimeout(() =&gt; this.isSaving[index] = false, 500);
  </code></pre>
  
  <p>and then unsub in my destroy hook:</p>
  
  <pre><code>ngOnDestroy() {
    this.subTimeout.unsubscribe();
  }
  </code></pre>
  
  <p>This gets laborious if I have to initiate several setTimeouts in my component. Is there an easier way to destroy them all? Like maybe with takeUntil(destroy$)?</p>