import { Component, OnInit } from '@angular/core'; import { FormBuilder, FormGroup, Validators } from '@angular/forms'; import { Router } from '@angular/router'; import { ContactService } from '../contact.service'; @Component({ selector: 'app-add-contact', templateUrl: './add-contact.component.html', styleUrls: ['./add-contact.component.css'] }) export class AddContactComponent implements OnInit { addContactForm: FormGroup submitted: boolean = false constructor(private formBuilder: FormBuilder, private router: Router, private contactService: ContactService) { } ngOnInit() {     this.addContactForm = this.formBuilder.group({ id: [], firstName: ['', Validators.required], lastName: ['', Validators.required], phoneNumber: ['', Validators.required] }); } onSubmit() { this.submitted = true if (this.addContactForm.invalid) { return } this.contactService.createContact(this.addContactForm.value).subscribe(data => { this.router.navigate(['list-user']) })   } }