rxjs: Observable.of(...).delay is not a function

In rxjs6 operators can be found in the 'rxjs/operators/*' packages.

import { delay } from 'rxjs/operators/delay';

of(values).pipe(
    delay(1000)
).subscribe(console.log);

In older versions can import the delay operator separately.

import 'rxjs/add/operator/delay';

In rxjs 6 this works fine:

import { Observable, of  } from 'rxjs';
import { delay } from 'rxjs/operators';

...    

const o = of(values).pipe(
  delay(10000)
);

o.subscribe( v => alert(v) );