After configuration reactive form

app.component.html

<div class="container">
  <div class="row">
    <div class="col-xs-12 mx-auto">
      <h1 class="display-4 text-center">Reactive Form Angular</h1>
      <form [formGroup]="myForm" (ngSubmit)="onSubmit()">
        <div class="form-group">
          <label for="nama">Nama</label>
          <input type="text" class="form-control" id="nama" formControlName="nama">
          <span class="text-danger" *ngIf="!myForm.get('nama').valid && myForm.get('nama').touched">Nama wajib diisi!</span>
        </div>
        <div class="form-group">
          <label for="email">Email</label>
          <input type="text" class="form-control" id="email" formControlName="email">
          <span class="text-danger" *ngIf="!myForm.get('email').valid && myForm.get('email').touched">Email belum valid!</span>
        </div>
        <div class="form-group">
          <label for="telepon">Telepon</label>
          <input type="text" class="form-control" id="telepon" formControlName="telepon">
          <span class="text-danger" *ngIf="!myForm.get('telepon').valid && myForm.get('telepon').touched">Nomer Telpon harus angka!</span>
        </div>
        <div class="form-group">
          <label for="email">Keterangan</label>
          <textarea formControlName="keterangan" name="keterangan" id="keterangan" class="form-control" rows="3"></textarea>
          <span class="text-danger" *ngIf="!myForm.get('keterangan').valid && myForm.get('keterangan').touched">Keterangan harus diisi!</span>
        </div>
        <button type="submit" class="btn btn-success" [disabled]="!myForm.valid">Simpan</button> &nbsp;
        <button type="button" class="btn btn-danger" (click)="onResetForm()">Reset</button> 
      </form>
        <div class="col-xs-12 mt-4" *ngIf="submitted">
              <h3 class="h3">Tampilan Data</h3>
              <p>Nama: {{ nama }}</p>
              <p>Email: {{ email }}</p>
              <p>Telepon: {{ telepon }}</p>
              <p>Keterangan: {{ keterangan  }}</p>
        </div>      
    </div>
  </div>
</div>