reactive-forms

import { AbstractControl, ValidationErrors, ValidatorFn } from '@angular/forms';

function hasActualValue(control: AbstractControl | null): boolean {
  return !!control && control.value !== null && control.value !== '';
}

import { Injectable } from '@angular/core';
import { HttpClient, HttpParams } from '@angular/common/http';
import { Observable, of } from 'rxjs';
import { catchError } from 'rxjs/operators';

export interface SearchResult {

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

@Injectable()
export class SignupFormService {
  readonly form: FormGroup;