title: How to check if form control is valid in Angular programatically?
body: <p>I need to check in the component (not in the template) if a control generated by formBuilder is valid. I tried:</p>
  
  <pre><code>if(this.miSpecialForm.controls.miName.dirty){
   console.log('Hi mom!');
  }
  </code></pre>
  
  <p>but I get the error:</p>
  
  <pre><code>Property 'miName' does not exist on type '{ [key: string]: AbstractControl; }'
  </code></pre>