@reactivex/rxjs/src/add/operator/delayWhen.ts

Reactive Extensions for modern JavaScript

import {Observable} from '../../Observable';
import {delayWhen, DelayWhenSignature} from '../../operator/delayWhen';

Observable.prototype.delayWhen = delayWhen;

declare module '../../Observable' {
  interface Observable<T> {
    delayWhen: DelayWhenSignature<T>;
  }
}