title: How to display validation error messages in Angular 2
body: <p>I want to create a form where the user will enter his First_Name and Last_Name. I'd like to validate those fields in client-side. <br><br>Is there any generic forms validator in Angular 2 and also I want show the error message in client-side. How to show error messages ? <br><br>
  Bellow is my code</p>
  
  <p>html file </p>
  
  <pre><code>&lt;form [formGroup]="myForm"  (ngSubmit)="submit()" &gt;
  &lt;ion-row&gt;
    &lt;ion-item&gt;
      &lt;ion-label primary floating&gt;FIRST NAME&lt;/ion-label&gt;
      &lt;ion-input type="text" id="firstname" class="form-control" formControlName="firstname"&gt;&lt;/ion-input&gt;
    &lt;/ion-item&gt;
  
   &lt;ion-item&gt;
     &lt;ion-label primary floating&gt;LAST NAME&lt;/ion-label&gt;
     &lt;ion-input type="text" id="lastname"  class="form-control" formControlName="lastname" &gt;&lt;/ion-input&gt;
   &lt;/ion-item&gt;
  &lt;/ion-row&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>ts file:</p>
  
  <pre><code>this.myForm = formBuilder.group({
     'firstname'  :  ['', Validators.compose([Validators.required, Validators.minLength(4), Validators.maxLength(10)])],
     'lastname'   :  ['', Validators.compose([Validators.required, Validators.minLength(1), Validators.maxLength(10)])],})
  </code></pre>
  
  <p>Backend Endpoint name and fields name:</p>
  
  <pre><code>submit(){
      let registerNewUserObj ={
         first_name:this.myForm.value.firstname,
         last_name:this.myForm.value.lastname
  </code></pre>