Angular 2 Reactive Forms - Detect input change event on component

Question

I would like to detect the value of change event to the input on form.component.ts. I would not like to call the function ex: (onChange) = "function($event.target.value)"

public form: FormGroup;  constructor(private formBuilder: FormBuilder){   }  private loadForm(){     this.form = this.formBuilder.group({         tipo: [null, Validators.required],         nomeRazao: [null, Validators.compose([Validators.required, Validators.minLength(3), Validators.maxLength(64)])],         apelidoFantasia: [null, Validators.compose([Validators.required, Validators.minLength(3), Validators.maxLength(64)])],         cpfCnpj: [null, Validators.compose([Validators.required, Validators.minLength(11), Validators.maxLength(14)])],         rgIe: [null],         contato: this.formBuilder.group({             email: [null],             telefone: [null]         }),         endereco: this.formBuilder.group({             cep: [null, Validators.pattern('^([0-9]){5}([-])([0-9]){4}$')],             uf: [null],             cidade: [null],             bairro: [null, Validators.required],             logradouro: [null],             complemento: [null],             numero: [null, Validators.pattern('/^\d+$/')]         })     }); }  ngOnInit() {     this.loadForm(); } 

Answer 1

You can subscribe to your form changes by using this :

this.form.valueChanges.subscribe(() => {    if (this.registerForm.controls['yourControlName'].value === 'someValue') {       //     }  }); 

Answer 2

For detecting changes in value of a particular field, 'valueChanges' event on that field can be subscribed, as shown below:

this.myForm.get('formcontrolname').valueChanges.subscribe(val => {     this.message = val;   });