title: How can I listen to valueChanges and setValue of a AbstractControl in reactive forms
body: <p>I am new to Angular and I have a Reactive Forms with  <code>AbstractControl</code> that subscribe for <code>valueChange</code> to listen for any values change in input field. Inside the subscribed function I want to change the value of the input under a certain condition.</p>
  
  <pre><code>this.abstractControl.valueChanges.subscribe(data =&gt; {
  ...
     if(.....) {
         this.formGroup.patchValue({
             name: result
         )}
      }
  ...
  }
  </code></pre>
  
  <p>I tried to use <code>this.abstractControl.setValue(result)</code> does'nt work too.</p>
  
  <p>I get an error in setting the value.</p>
  
  <pre><code>ERROR RangeError: Maximum call stack size exceeded
  </code></pre>
  
  <p>What is the recommended way of listening to a value change and changing the value accord to a condtion?</p>