validate the form validity

validity.js

// Check Validation status inside FormGroup/FromArray
const invalidControls: string[] = [];
const recursiveFunc = (form: FormGroup|FormArray) => {
  Object.keys(form.controls).forEach(field => {
    const control = form.get(field);
    if (control.invalid) { invalidControls.push(field); }
    if (control instanceof FormGroup) {
      recursiveFunc(control);
    } else if (control instanceof FormArray) {
      recursiveFunc(control);
    }
  });
};
recursiveFunc(this.validateForm);
console.log(invalidControls);