Accessing a Service inside a static method

Ionic Framework ionic-v3
8

OK, I would try creating the validator as a lexically scoped closure variable instead of having it be a method. Something like this:

let validator = (control) => {
  return this.injectedThingy.doSomething(control); 
};

this.nameControl = new Control('', , validator);

Another option would be to refactor your validator into its own class, which can use DI in its constructor:

@Injectable()
class AsyncValidator {
  constructor(private _svc:SomeService) {
  }

  validate(control:Control):Promise<ValidationResult> {
    return this._svc.doSomething(control);
  }
}

@Injectable()
class FormHavingPage {
  constructor(fb: FormBuilder) {
    fb.group({
      'name': ['', , AsyncValidator]
    });
  }
}

You can use a class name for a validator instead of a function as long as DI can instantiate it and it has a method named validate. Untested code, sorry for syntax errors.