Inject custom service into a custom Validator

Question

I\'m trying to make a custom Angular 2 form Validator to check if a user exist on a data base.

This is the code of my custom form Validator

Answer 1

@Injectable()
export class EmailValidator {

  constructor(private api:API) {}

  /* static */ checkEmail(control: FormControl,): any {
    return this.api.checkUser(control.value).then(response => {
      response;
    });
  }
}

Add it to of @NgModule() or @Component() depending on what scope you want it to have

providers: [EmailValidator]

Inject it to the component where you want to use it

export class MyComponent {
  constructor(private emailValidator:EmailValidator, fb:FormBuilder){}

  this myForm = fb.group({
    email: [], [this.emailValidator.checkEmail.bind(this.emailValidator)]
  });
}