index.ts

import { mergeMap, switchMap, take, mapTo, map } from 'rxjs/operators';
import { fromPromise } from 'rxjs/observable/fromPromise';
import { of } from 'rxjs/observable/of';
import { interval } from 'rxjs/observable/interval';
import { request } from 'universal-rxjs-ajax';

const getIt = () => 
  fromPromise((async () => {
    await Promise.resolve();
  })()).pipe(switchMap(() => request({ url: 'https://api.github.com/users/ajcrites' })
    .pipe(map((response: any) => response.response.login))));

interval(10)
  .pipe(take(2), switchMap(() => getIt()))
  //.pipe(take(2), switchMap(() => request({ url: 'https://api.github.com/users/ajcrites' })
    //.pipe(map((response: any) => response.response.login))))
  .subscribe(console.log);