Default Validator

import { FormGroup, FormBuilder, Validators } from '@angular/forms';

export class HomeComponent {
  userForm: FormGroup;

  constructor (formBuilder: FormBuilder) {
    this.userForm = formBuilder.group({
      name: ['', Validators.required],
      email: '',
      address: formBuilder.group({
        country: '',
        city: '',
      })
    });
  }
}