title: Angular Reactive forms : change vs valueChanges
body: <p>I am using <a href="https://angular.io/guide/reactive-forms" rel="noreferrer">reactive forms</a> in Angular 7.</p>
  <p>I have many fields that are dependent on other fields.</p>
  <p>What I am curious about of what should I use <code>(change)</code> or <code>this.form.get(&quot;control_name&quot;).valueChanges</code>?</p>
  <p>For ex. if both will work on inputs then I want to know difference, pros &amp; cons between them.</p>
  <p>Which is better with performance?</p>